# Chemical Reactions and Chemical Equations

Prof. Liwayway Memije-Cruz is an author, educator and speaker. She teaches science subjects in different universities and colleges.

## Introduction

A chemical reaction is all about chemical change. The ripening of fruits, photosynthesis, tarnishing of iron, burning of woods, digestion of foods, and even cooking foods are few examples of chemical changes and chemical reactions happening around us and even inside our bodies. A chemical reaction involves the transformation of one or more substances into another substance or substances. it involves a change in composition and is represented by a chemical equation.

A chemical equation provides a concise picture of a chemical change. It is used to convey the pertinent information about the chemical reaction which includes the substances involved and their quantitative ratio.

Chemical equations are representations of chemical reactions in terms of symbols of elements and formulas of compounds involved in the reactions. The substances that enter into a chemical reaction are called reactants and the substances formed are the products.

## Writing and Balancing Chemical Equations

Steps in Writing a Balance Equation

1. Write the symbols and formulas of the reactant/s on the left side of the arrow and symbol/s and formula/s of the products on the right. Monoatomic elements are represented by their symbols without subscript. Examples: Ca, Mg and Zn. Diatomic elements are represented by their symbols with subscript 2. Examples: H2, O2, N2, F2, CI2, Br2 and I2
2. Chemical changes occur in accordance with the Law of Conservation of Mass. It is therefore necessary to balance the number of atoms of each element in the reactants with the number of atoms of the same element in the product. Balancing chemical equations by inspection simply requires placing the coefficient before any of the symbol/s and formula/s until there are exactly the same numbers of each kind of atom on both sides of the equation.
• Pointers to consider in using coefficient:
1. There is no need to write a coefficient, which is 1.
2. Use simplest whole numbers as coefficients.

Example:

Write the balance chemical equation for the reaction of hydrogen with oxygen to produce water.

2 H2 + O2 2H2O

“The reaction of 2 moles of hydrogen and 1 mole of oxygen yields 2 moles of water”.

## Types of Chemical Reactions

1. Combination reaction is a type of reaction in which two or more substances (either elements or compounds) react to form one product.

Example: 2 Na + Cl2 → 2NaCl

2. Decomposition reaction is a type of reaction in which one compound decomposes to form two or more new substances. Usually heat is to cause these reactions to take place.

Types of Decomposition reaction:

a. Hydrates - when heated, decompose to yield water and anhydrous salt. A hydrate is a salt that contains one or more molecules of water for each formula unit of salt, built right into the crystal structure.

Example: BaCl2 2H2O → BaCl2 + 2H2O

b. Chlorates – when heated, decompose to form chlorides and oxygen gas.

Example: 2KCIO3 → 2KCI + 3O2

c. A few metal oxides decompose when heated to form the free metal and oxygen gas.

Example: 2HgO → 2Hg + 02

d. Most carbonates when heated, decompose to form oxides and CO2.

Example: CaCO3 → CaO + CO2

The group IA carbonates do not decompose readily.

e. Most hydrogen carbonates (bicarbonates), when heated decompose to form an oxide plus water and CO2.

Example: Ca(HCO3) → CaO = 2CO2 + H2O

When hydrogen carbonates of the Group IA metals are heated they form a carbonate plus water and CO2.

Example: 2NaHCO3 → Na2CO3 + CO2 + H2O

3. Substitution or Replacement reaction is a type of reaction in which a metal replaces another metal ion from a solution or a nonmetal replaces a less active nonmetal in a compound.

The activity series is used to predict the products of replacement reaction. In using this series, any free metal that is higher on the list will displace from a solution another metal that is lower. Hydrogen is included in the series although it is not a metal. Any metal above hydrogen in the series will displace hydrogen gas from an acid.

## Activity series of metals

4. Double Decomposition reaction is a type of reaction wherein two compounds react to form two new compounds. This involves exchange of ion pairs.

Examples:

AgNO3 + HCI → AgCl +HNO3

Ba(NO3)2 + 2NaOH → Ba (OH)2 + 2NaNO3

## Oxidation Numbers

Oxidation numbers are arbitrary numbers based upon the following rules:

1. The oxidation number of uncombined elements is zero.

2. The common oxidation state of hydrogen in compound is +1, -1 for hydrites. For oxygen, it is -2.

3. The common oxidation state for Group VIIA elements in binary compounds is -1. It varies in tertiary compounds.

4. The common oxidation state for Group IA ions is +1; for Group IIA is +2, and for Group IIIA is +3.

5. The oxidation state for an ion is calculated if the oxidation states of all other ion in the compound are known, since the sum of all oxidation states in a compound is zero.

Examples:

1. Calculate the oxidation state of Mn in KmnO4.

Assign the oxidation number of the other ions and let x be the oxidation number of Mn.

+1 x -2

K Mn O4

Applying rule no. 5

(+1) + (X) + (-2)4 = 0

1 + X -8 = 0

X = +7

Therefore the oxidation state of Mn in KMnO4 is +7

2. Calculate the oxidation number of Cl in Mg(ClO3)2.

+2 X -2

Mg (Cl 03)2

(+2) 1 + (X) + (-2)6 = 0

X = +5

Therefore the oxidation state of Cl in Mg(ClO3)2 is +5

## Oxidation-Reduction Reactions

Oxidation is a chemical change in which electrons are lost by an atom or group of atoms, and reduction is a chemical change in which electrons are gained by an atom or group of atoms. A transformation that converts a neutral atom to a positive ion must be accompanied by the loss of electrons and must, therefore, be an oxidation.

Example: Fe = Fe+2 + 2e

Electrons (e) are written explicitly on the right side and provide equality to total charge on the two sides of the equation. Similarly, the transformation of neutral element to an anion must be accompanied by electron gain and is classified as a reduction.

Examples:

Cl2 + 2e = 2Cl­­­-

S + O2 → SO2

Since the oxidation number of the sulfur atom increase from 0 to +4, sulfur is said to be oxidized. The oxidation number of the oxygen atom decreases from 0 to -2, then the oxygen is said to be reduced.

In an oxidation-reduction reaction, the substance that is oxidized is called the reducing agent since it is causes something else to be reduced. On the other hand, the substance that is reduced causes something else to be oxidized and it is called oxidizing agent.

## Oxidation Number Method of Balancing Oxidation-Reduction Equations

Given the following expression:

HNO3 + H2S → NO + S + H2O

Balance the redox reaction using the oxidation number method:

1. Determine the oxidation numbers of the atoms/ions in the equation in order to identify atoms/ions undergoing oxidation or reduction.

HNO3 + H2S → NO + S H2O

Nitrogen is reduced from +5 to +2, a decrease of 3, and sulfur is oxidized from -2 to 0, an increase of 2.

2. Balance the total increase and the total decrease of oxidation number by placing the necessary coefficients, using the smallest number possible.

We have a decrease of 3 and an increase of 2 as indicated in the unbalanced expression. The lowest common multiple of 3 and 2 is 6. Since:

(-1) (2) = -6

(+2) (3) = +6

Therefore:

2HNO3 + 3H2S → 2NO + 3S + H2O

3. Complete the balancing by inspection.

Balance those substances that changed in oxidation number and then any atoms other than hydrogen and oxygen. Then finally balance hydrogen and oxygen.

2HNO3 + 3H2S → 2NO + 3S + 4H2O

HNO is the oxidizing agent and H2S is the reducing agent.

## Factors Affecting The Rates of Chemical Reactions

For a chemical reaction to take place, the molecules/ions of the reacting substances must collide. However, not all collisions may result to chemical change. For a collision to be effective, the colliding particles must be in the right orientation and must possess the necessary energy to reach the activation energy.

Activation energy is the added energy that reacting substances must have in order to take part in a chemical reaction. Any factor that affects the frequency and effectiveness of collisions of reacting substances also affects the rate of chemical reaction, which is the rate of formation of products or the rate of disappearance of reactants. These rates maybe affected by the following factors:

1. Nature of Reactants

The nature of the reactants determines the nature of the activation energy or the height of the energy barrier that must be overcome in order for the reaction to take place. Reactions with low activation energy occur rapidly while those of higher activation energy occur slowly. Ionic reactions occur rapidly since the ions have an attraction for each other and therefore do not need additional energy. In covalent molecules, the collisions may not be enough to break the bonds, hence have higher activation energy.

2. Concentration of Reactants

Concentration of a substance Is a measure of the number of molecules in a given volume. The rate of reaction of reaction increases as the molecules become more concentrated and become more crowded, hence, there is an increase in the frequency of collisions. Concentration can be expressed as moles per liter for reactions carried out in liquid solutions. For reactions involving gases, the concentration is expressed in terms of the pressure of the individual gases.

3. Temperature

An increase in temperature will cause the molecules to move rapidly resulting in more collisions. Because they are moving rapidly, they have sufficient energy and they collide with greater impact.

4. Catalyst

A catalyst is a substance that alters the speed of reaction without itself undergoing a permanent chemical change. Catalyst are usually used to increase the speed of chemical reaction, but there are also catalysts called inhibitors or negative catalysts, which slow down a chemical reaction.

Example:

2SO2 + O2 → 2SO2 (SLOW)

2NO + O2 → 2NO2 (FASTER)

The catalyst forms an intermediate compound with one of the reactants.

NO2 + SO2 → SO3 + NO

The catalyst is regenerated

Catalysts are important in industrial processes because aside from increasing the production, their use cut off production cost. Enzymes, which are the biological catalysts, metabolize reactions in our body.

Example:

Invertase cleaves sucrose (table sugar) into simple sugars, glucose and fructose, glucose in the form absorbed in the bloodstream

## Questions for Study and Review

I. Write a balanced equation that describes each of the following chemical reactions:

1. When heated, pure aluminum reacts with air to give Al2O3.
2. CaSO4 • 2H2O, decomposes when heated, giving calcium sulfate, CaSO4, and water.
3. During photosynthesis in plants, carbon dioxide and water are converted into glucose, C6H12O6, and oxygen, O2.
4. Water vapor reacts with sodium metal to produce gaseous hydrogen, H2, and solid sodium hydroxide, NaOH.
5. Acetylene gas, C2H2, burns in air forming gaseous carbon dioxide, CO2 and water.

II. Balance the following equations and indicate the type of reaction:

1. K + CI → KCI
2. AI + H2SO4 → AI2(SO4)3 + H2
3. CuCO3 + HCI → H2O + CO2
4. MnO2 + KOH → H2O + K2MnO4
5. AgNO3 + NaOH → Ag2O + NaNO3
6. C6H6 + O2 → CO2 + H2O
7. N2 + H2 → NH3
8. Na2CO3 + HCI → NaCI + CO2 + H2O
9. MgCI2 + Na3PO4 → Mg3(PO4)2 + NaCI
10. P2O5 + H2O → H3PO4

III. Balance the following redox equations using the oxidation number method. Be able to identify the oxidizing and reducing agent.

1. HNO3 + H2S → NO + S + H2O
2. K2Cr2O7 + HCl → KCl + Cr + Cl2 + H2O + Cl

IV. Choose the condition, which will have a higher reaction rate and identify the factor affecting the rate of reaction.

1. a. 3 moles of A reacting with 1 mole of B

b. 2 moles of A reacting with 2 moles of B

2. a. A2 + B2 ----- 2AB at 200 C

b. A2 + B2 ----- 2AB at 500 C

3. a. A + B ----- AB

b. A + C ----- AC

AC + B ----- C

4. a. Iron exposed in moist air

b. Silver exposed in moist air

Thania Bucao on October 10, 2018:

Chemical reactions can be quite complicated and tricky, but I can appreciate it now because of your blog post ma'am. Without putting in an extra amount of effort, understanding this type of subject or topic will really be hard. Thank you ma'am for this insightful post, now I have a deeper understanding about chemical reactions. :)

ESTRELLA, JERICHO E. on October 09, 2018:

Indeed, a greater appreciation of one's subject is another way of breaking ignorance.Life is quite complicated when you don't know this concepts, when you're an uneducated person you tend to believe in "akala" or "chismis". Hence, even though life is complicated on its nature as a human we need to appreciate this complexity? How? By educsting yourselves with this course "chemistry" specially because we humans on its own are a chemical factory itself. Why? Because those aha moments coming from your teachers or book reference will give you an insightful and more profound perception around you.

Pauline Venzon on August 21, 2018:

Venzon, Pauline Charm S. (BSMT-1)

Chemical reaction helps us to understand the properties of matter. It explains how the natural world works. All the substances in daily life are the result of chemical change. Therefor, without chemical reactions, nothing would ever change and no organism could live.

Krichelle kae Calderon Enriquez from San Miguel, Bulacan, Philippines on August 01, 2018:

Enriquez, Krichelle kae C. (BSMT 1), Chemical Reaction is a process that leads to chemical transformation of one set of chemical substances to another. I’ve learned a lot about the chemical reaction. Thank you to this slides because it helps a lot especially on my lessons.

Enriquez, Krichelle Kae C. on August 01, 2018:

Chemical reaction is a process that leads to the chemical transformation to another chemical substance. This slode share helps me to define what is a chemical reaction is and what happens during the chemical reaction.

Jeriemae DelaCruz on August 01, 2018:

Jeriemae Dela Cruz BSMT 1

i learned that each chemical when combined to other chemical has different time or rate of reactions.

trixie anne on August 01, 2018:

SILVESTRE, TRIXIE ANNE C. BSMT 1 I learned about what chemical reaction is because of this slides, Considering the abundance of substances in and around us, it is not unusual to observe examples of chemical reactions in everyday life. Look at the things around you, nearly all of them are made up of some sort of substances, which are further classified into element, mixture, alloy, etc. And speaking in chemistry terms, the air we breathe is a mixture in gaseous state, while water is a compound existing in liquid state.

Joyce Nicole on August 01, 2018:

Dungo, Joyce Nicole B. (BSMT 1) - Chemical reactions are how new forms of matter are made and it occurs when molecules interact and change. Without chemical reactions, nothing would ever change and no organisms could live.

Allen Tuazon BSMT on August 01, 2018:

Tuazon, Allen Patrick F. (BSMT-1)

Chemical reaction is a process were each substance or elements react and converted to one or different substance that may result a new and improved element that may use in other purposes that other elements cannot be used.

Pauline Venzon on August 01, 2018:

Venzon, Pauline Charm S. (BSMT-1)

The Chemical reaction is a process in which one or more substances the reactants are converted to one or more different substances the products. A chemical reaction rearranges the constituent atoms of the reactants to create different substances as products and helps us to understand the properties of matter , without chemical reaction nothing would ever change and no arganism could live.

Jimelle Conson from Bulacan on August 01, 2018:

CONSON, JIMELLE - BSMT1. Chemical Reactions and Equations involves different changes and equations. This slideshare enables us to know more about the different topics regarding reactions and equations. Which plays an important role in our daily lives

Tricia Anne Reyes BSMT from Palapala, San Ildefonso Bulacan on July 31, 2018:

REYES, TRICIA ANNE I. BSMT

Chemical Reaction is a process that involves rearrangement of the molecular or ionic structure of a substance, as opposed to a change in physical form or a nuclear reaction.In this lesson, I've learned that elements or substance may undergo reaction and it varies to its chemical properties. This chapter is very essential to our course because it has something to do with chemicals and it has gave us knowledge about different chemical reactions.

pascualangelou on July 31, 2018:

Pascual, Mary Angelou C. ( BSMT-1)

After we learned the chemical bonding, it is important for us to study the chemical reactions and equation for us to know the proper way of naming new substances and how to write a chemical formula.

chemical reactions which described with chemical equation that present a product and reaction conditions.

This lesson is a great help and relevant for us as a medical technology student when in comes in our laboratory experiment which is we mixed a lot o chemical reagent and we need to name the product of that compound mixture

John Derrick Chan on July 31, 2018:

CHAN, JOHN DERRICK L. (BSMT1) Chemical reaction is define as interaction of an element/compound to another element/compound to form a product. In this lesson, we learned the behaviors of different element when it comes to reacting with another element. The reaction won't always be the same. It will depend on the substance. This lesson is very important in our course since, we need to have a brief background about different substances since, in the future we will conduct tests on different specimen (mixture) to identify some data which are also about elements. And so, there will be reactions to occur and if you already have some prior knowledge, we can do things efficiently.

Emman Payuran on July 31, 2018:

Villasenor, Emmanuel P. (BSMT 1)

A chemical reaction is a process that leads to the transformation of one set of chemical substances to another. The substance (or substances) initially involved in a chemical reaction are called reactants or reagents. Chemical reactions are usually characterized by a chemical change, and they yield one or more products, which usually have properties different from the reactants. Chemical reactions are described with chemical equations, which symbolically present the starting materials, end products, and sometimes intermediate products and reaction conditions

Kimberly Reforsado on July 31, 2018:

It is evident that there are a lot of chemical changes that happened in our surroundings in daily basis. Through the knowledge about chemical reactions and equations, we are able to understand these changes and how they happen simply because equations are illustrations of chemical reactions through the use of symbols that will allow us to understand much more easier. Also, if we have the prior knowledge about chemical reactions, as a medical technologist in the future, we will not have difficulty in comprehending the change in the substances or chemicals we are going to handle and deal with in the future.

Darah Arthria Cristobal from San Ildefonso, Bulacan on July 31, 2018:

CRISTOBAL, DARAH ARTHRIA DC. BSMT1. A chemical reaction is a chemical change which forms new substances. It may be represented by a chemical equation, that indicates the number and type of each atom. A chemical equation uses the element symbols as shorthand notation for the elements.

kathlenecalague on July 31, 2018:

CALAGUE KATHLENE JADE BSMT1 Chemical reactions are one of the most important things that happen in our everyday lives. It is through chemical reactions why humans reproduce, grow, heal, and digest. So without chemical reaction, we could not be able to sustain life as easy as it is right now.

KristineCassandra on July 31, 2018:

Jota, Kristine Cassandra B.

BSMT 1

Chemical reaction is all about chemical change, it involves the transformation of one substance into another substance. In this lesson the best example of a chemical reaction are ripening of fruits, photosynthesis, tarnishing of iron, burning of woods, digestion of foods and even cooking etc. We also learned how to balance chemical equations with the help of this. And also the factors that can affect chemical change.

Elaine Herrera on July 31, 2018:

HERRERA, MARY ELAINE V. (BSMT) Chemical reactions are at the heart of virtually every physical and biological process on the universe. Life developed on earth as a result of chemical reactions. even our ability to think and move is a result of chemical reactions that occur within our bodies. By observing chemical reactions, we are able to undrerstand and explain how the natural world works. Without these. nothing would ever change. atoms would stay atoms. New molecules wouldn't form. no organisms would live. If matter didn't react with matter, the universe would be extremely boring!

De Leon, Melody Jane S. on July 31, 2018:

Chemical reaction was all about the changing of some substances or presence of another element in substances. In this lesson the best examples of chemical reaction nor changing are: ripening of fruits, rusting iron, blood, urinalysis and more. Also, the balancing in this chapter it taught us the no. of moles, atoms and mass.

Ma. Roselle Angela S. de Leon on July 31, 2018:

BSMT 1

Chemical reaction is all about chemical change. It's how an object change through chemical reactions. This changes occur in color, odor, precipitation and etc. In this lesson, we also learned the different factor that affect chemical change. with these, we can now have the knowledge about how chemicals react and undergoes change.

anjelacastro2 on July 31, 2018:

CASTRO, ANJELA V. (BSMT-1) - Chemical equation gives us information about the changes that occurred in a chemical reaction. In order to write the chemical equation, we should know the formula of the elements or compounds which are involved in the chemical reaction. After writing the chemical reaction it is important to balance the equation. Balancing of chemical equation is important to maintain equality of number of moles, atoms and mass on both sides (reactant and product sides) of the equation for the reaction.

Abe Puzon from Bulacan, Philippines on July 31, 2018:

Puzon, Abegail S. (BSMT-1)

By observing chemical reactions, we are able to understand and explain how the natural world works. Chemical reactions turn food into fuel for your body, make fireworks explode, cause food to change when it is cooked, make soap remove grime, and much more. Without chemical reactions, nothing would ever change. Atoms would stay atoms. New molecules wouldn't form. No organisms could live. If matter didn't react with other matter, the universe would be extremely boring!

Nhiza Mae Fajardo on July 31, 2018:

Fajardo, Nhiza Mae A. BSMT-1

This article about chemical reaction and equation contribute a lot to me. I have learned about combining elements and also have the knowledge of what elements should and shouldn't be combined. That knowledge is relevant to us, medical technology students.

Chloe Bundalian on July 31, 2018:

Bundalian, Chloe Jane L. BSMT 1 -Chemical reactions and equations is very useful/important to us especially we, the med students. We are going to observe on what will happen if we are going to combine elements.

Pinky Miranda on July 29, 2018:

MIRANDA, MA. PINKY RAMEI V. (BSMT 1) - As a medical technology student, it is really needed for us to study chemical reactions and equations because after we learn the chemical bonding and proper way of naming and writing chemical formulas, we should know what happens next. How two elements react with each other? and what is now the chemical equation? And changes will occur in this situation so there is a need for us to go back to the lesson of physical and chemical change because in writing chemical equations, it is important to know if the element or compound is a Solid, Liquid, Gas or Aqueous and what process does it undergoes. Because in line with that, there are 4 chemical reactions that you will encounter because there is reactant and products.

By studying this, we will be able to identify or prove the reaction happened to the chemicals because as a medtech students we mixed a sample with a reagents. and we will be familiarized with how does a chemical/sample react with another.

John Lawrence Delos Santos on May 06, 2018:

As a student we must study chemical reactions and equation cbeacause it helps us more deeper understanding about it .A chemical equation provides a concise picture of a chemical change. It is used to convey the pertinent information about the chemical reaction which includes the substances involved and their quantitative ratio.

Chemical equations are representations of chemical reactions in terms of symbols of elements and formulas of compounds involved in the reactions. The substances that enter into a chemical reaction are called reactants and the substances formed are the products.

carlo crisanto v sapiendante on April 29, 2018:

CARLO CRISANTO V. SAPIENDANTE

chemical reaction ca help us to understand further more in our cheisrty subject. it described the chemical reactions.also we can learn the chemical interaction. everthing that we do involves chemical reaction. we may not see it but theres a chemical reaction on what we are doing. without chemical reaction there would be hormonal imbalance in each individuality. thats why chemical reaction is needed.

CRUZ, BEATRIZ DL. BS PSY3 on April 25, 2018:

A thermite reaction using iron(III) oxide. The sparks flying outwards are globules of molten iron trailing smoke in their wake.

A chemical reaction is a process that leads to the transformation of one set of chemical substances to another.[1] Classically, chemical reactions encompass changes that only involve the positions of electrons in the forming and breaking of chemical bonds between atoms, with no change to the nuclei (no change to the elements present), and can often be described by a chemical equation. Nuclear chemistry is a sub-discipline of chemistry that involves the chemical reactions of unstable and radioactive elements where both electronic and nuclear changes can occur.

The substance (or substances) initially involved in a chemical reaction are called reactants or reagents. Chemical reactions are usually characterized by a chemical change, and they yield one or more products, which usually have properties different from the reactants. Reactions often consist of a sequence of individual sub-steps, the so-called elementary reactions, and the information on the precise course of action is part of the reaction mechanism. Chemical reactions are described with chemical equations, which symbolically present the starting materials, end products, and sometimes intermediate products and reaction conditions.

Tedyliza Ramos on February 02, 2018:

RAMOS TEDYLIZA ROSE

BSTM 4

Chemical reactions help us understand the properties of matter. By studying the way a sample interacts with other matter, we can learn its chemical properties. These properties can be used to identify an unknown specimen or to predict how types of matter might react with each other.

Tedyliza Ramos on January 18, 2018:

RAMOS TEDYLIZA ROSE C.

BSTM 4

TUTORIAL-FRIDAY

Chemical reactions are described with chemical equations, which symbolically present the starting materials, end products, and sometimes intermediate products and reaction conditions. chemical reactions are used in combinations during chemical synthesis in order to obtain a desired product.

Jerielen Mangahas on January 18, 2018:

Jerielen Mangahas

BSTM4 (FRIDAY-TUTORIAL)

A chemical reaction is a chemical change which forms new substances. A chemical reaction may be represented by a chemical equation, which indicates the number and type of each atom, as well as their organization into molecules or ions.

ivoryshanesalonga on January 18, 2018:

ivory shane salonga

BSTM IV

Chemical reactions takes place in plants and animals, this result in the formation of substances in some plants and animals that can be used to treat illness. Chemical reactions are one of the most important types of events in the universe. It's through chemical reactions that plants grow, process food, and can compost for new plants. It's because of chemical reactions that human beings and all other animals reproduce, digest, grow.

Rene Briane on August 18, 2017:

Rene Briane G. Angeles

BSEEC-III

All the substances in daily life are the result of chemical change. Therefor, without chemical reactions, nothing would ever change and no organism could live

Melen on August 17, 2017:

Melencio, Marc James

Tourism

Chemical reaction, a process in which one or more substances, the reactants, are converted to one or more different substances, the products.

Christian Paul V. Ogorida BSCE II on August 17, 2017:

Chemical Reaction is like a building we as an engineers make a foundation and we will measure it, in the right procedure:)

Christine San Gabriel BSN1 on August 17, 2017:

When elements are mixed together there will be a reaction that will form a equation.There is no such thing that just popped in this world from nothing.Everything has origin in which these equations are showing.

Ronniel Legaspi on August 17, 2017:

LEGASPI, RONNIEL AERON R.

BSEEC-3

Chemical reaction is like building new chemical that help us in future like medicine. As a future engineer knowing how the chemicals react in each other is like making new things for the brightest future.

Camille San Mateo on August 17, 2017:

SAN MATEO, CAMILLE C.

BSN-1

Everyday we encounter different changes or reactions. Chemical equation is symbolic representation of the chemical reaction. When there are changes there are new materials because all materials are made of chemicals. Chemical reactions involves interaction between chemicals that all reactants changed into new materials. And the properties of those new materials are different from the reactants.

Bryan Pangilinan on August 17, 2017:

Bryan P, Pangilinan

BSHM 4-2

A chemical reaction is the change of a substance into a new one that has a different chemical identity. A chemical reaction is usually accompanied by easily observed physical effects, such as the emission of heat and light, the formation of a precipitate, the evolution of gas, or a color change. Absolute confirmation of a chemical change can only be validated by chemical analysis of the products. Chemical reactions help us understand the properties of matter. It is important to balance chemical equations because there must be an equal number of atoms on both sides of the equation to follow the Law of the Conservation of Mass. This chemical law states that in order for the equation to be correct, "An equal quantity of matter exists both before and after the experiment; the quality and quantity of the elements remain precisely the same." In the field of teaching, teachers must possess good doings because students tend to imitate their teachers. Teachers can be similar to chemical reaction because they might change the lives of their students. They let their student's lives transform into new beginning.

Teddy Gullem on August 17, 2017:

Chemical reactions creates new substances that can be useful in our daily life. It is a process which one or more reactants converts to one or more different products. A chemical equation is the symbolic representation of a chemical reaction in the form of symbols and formulas.

Danica Vipinoza on August 16, 2017:

Chemical reaction, a process in which one or more substances, the reactants, are converted to one or more different substances, the products. Substances are either chemical elements or compounds.

A reaction is how chemical change occurs. A chemical reaction occur when matter interacts with other matter to make new products. It helps us understand the properties of matter. By studying the way a sample interacts with other matter, we can learn its chemical properties.

Jasper Sierto on August 16, 2017:

Sierto, Jasper L.

BSHM - 3

Chemical reaction, a process in which one or more substances, the reactants, are converted to one or more different substances, the products. Substances are either chemical elements or compounds. A chemical reaction rearranges the constituent atoms of the reactants to create different substances as products.

A chemical equation is shorthand that scientists use to describe a chemical reaction. Let's take the reaction of hydrogen with oxygen to form water as an example. If we had a container of hydrogen gas and burned this in the presence of oxygen, the two gases would react together, releasing energy, to form water.

Javy Paul Gonzales from San Ildefonso Bulacan on August 16, 2017:

GONZALES, JAVY PAUL S.

BSHM 3

it is the reason why all living organisms maintain their lives on their life span. It is the most important of all about cells because it includes the important process of cells (Membrane Transport, Photosynthesis, Protein Synthesis, Cell Division, and cellular Respiration) that essential to us to be learned.hemical reactions are described with chemical equations, which symbolically present the starting materials, end products, and sometimes intermediate products and reaction conditions.

RUSSELL BERNARDINO BSTM4 on August 15, 2017:

Chemical reactions are taking place within our body, and outside in our natural environment all the time. However, we may not know about it unless we study or read about them, and then understand them. Most of the chemical reactions are not visible to our naked eye.

These chemicals can be applied in many ways like in the kitchen. The kitchen is the ideal lab where people can experience various chemical reactions and even study them. They need not do anything special. They can simply do what they do in the kitchen everyday and still observe the chemical reactions that occur.

Everything on earth is made up of chemical REACTIONS : you, your food, and the products we use in our daily lives such as soaps, perfumes etc. all are made up of chemicals. Life without chemical reactions is impossible.

Jolina Gabriel on August 14, 2017:

Jolina Gabriel

BSN -1

Chemical reactions must be distinguished from physical changes. Physical changes include changes of state, such as ice melting to water and water evaporating to vapour. If a physical change occurs, the physical properties of a substance will change, but its chemical identity will remain the same. No matter what its physical state, water (H2O) is the same compound, with each molecule composed of two atoms of hydrogen and one atom of oxygen. However, if water, as ice, liquid, or vapour, encounters sodium metal (Na), the atoms will be redistributed to give the new substances molecular hydrogen (H2) and sodium hydroxide (NaOH). By this, we know that a chemical change or reaction has occurred.

Dave Joshua Villangca on August 14, 2017:

Dave Joshua B. Villangca

BSN-I

Baliuag University

General Chemistry

T, F 7:30-12:00

Truly, Photosynthesis is the most important chemical reaction in this world. It is because without it, foods that comes from the plants which are vegetables and rice will not become possible, and food is one of the basic need of a human. Chemical reactions also occurs in our body like turning foods into energy which enables us to do works. In this link, I learned how to balance equations, but I also learned that balancing equation is quite difficult because it requires patience, understanding and critical thinking. Once we have those values then it will become easier to balance. We just have to practice and practice so that we can understand it and master it.

As a nurse, it is important to learned how to balance equations for us to understand also how chemical reactions in our body occurs and produced.

TORIBIO, PAULINE LOUISE A. on August 14, 2017:

TORIBIO, PAULINE LOUISE A.

BSN I

Chemical reactions happens everyday. Just by simply chewing the food and digesting it, there is a chemical reaction. An equation shows how new substance or substances are formed. In everyday lives we encounter a reaction. Learning these equations and reactions, balancing them is part of chemistry. As well as part of our everyday lives. Everything in chemistry may innovate our lives. That is why Chemistry is an essential subject to learn.

Gil Calderon on August 14, 2017:

Observations that suggest a chemical reaction is taking

place are the evolution of energy as heat and light, the production

of gas, a change in color, and the formation of a precipitate.

A balanced chemical equation represents, with symbols and

formulas, the identities and relative amounts of reactants and

products in a chemical reaction

Bianca Bernardo on August 10, 2017:

MARUCOT, KATRINA BIANCA BSN1

Everything in this world have their own chemistry. Everything we know have their own chemical names, chemical formulas, thus chemical equations and reactions. To create something, whether for agriculture, economic, medical use, everything have their own composition. Even us humans, we have our own different compositions which is why Chemical Reactions are in each and everyone of us, Especially in our own human body which is known to be the biggest laboratory there is.

Jjjjkk on June 14, 2017:

Good

Aldrinsntg on February 25, 2017:

Aldrin L Santiago BSPSY II

chemical reactions A chemical reaction is an irreversible change and produces different things.

Different Chemicals Reactions Acid Rain Hydrochloric acid

Aluminum Metallic powder: Will react very dangerously when combined with acids. Magnesium Metal Global Warming: It is not a chemical reaction but is a consequence of a long chain of chemical reactions. Chemical weapons: Are the most dangerous, harmful chemical reactions ever made. How does Acid rain happen? Because of pollution in the air, acid gases from factories, cars and homes, the rain is becoming dangerous for the life of any living creature because it contains poisonous chemicals. Acid gases are produced when fossil fuels such as coal and oil are burned in power stations, factories or our homes. Most of these acidic gases are blown into the sky, where they will mix with the clouds, it can cause rain, snow, sleet or hail to become more acidic.

Jahna Carmella B. Galvez on February 25, 2017:

Jahna Carmella B. Galvez

BEED -II

Chemical reactions takes place in plants and animals, this result in the formation of substances in some plants and animals that can be used to treat illness. Chemistry is important to everyday life, because it provides medicine. The food we consume each day comes directly from chemical processes.

Salvador, Jucel Roma M. on February 25, 2017:

A reaction is how chemical change occurs. A chemical reaction occur when matter interacts with other matter to make new products. It helps us understand the properties of matter. By studying the way a sample interacts with other matter, we can learn its chemical properties. While chemical equation is an expression of a chemical process that uses symbols and formulas instead of words to describe the changes. Reactants are the substances that combine in the reaction and products are the substances that are formed by the reaction. In balancing chemical equations, we have to consider a lot of rules. It is essentially done by trial and error because there are a lot of ways and systems of doing this. But it is important to count the number of atoms in an equation.

Sean Rick Ledesma BAC-II on February 25, 2017:

A chemical equation is the symbolic representation of a chemical reaction in the form of symbols and formulae, wherein the reactant entities are given on the left-hand side and the product entities on the right-hand side.

Rafael Adriano on February 24, 2017:

A chemical reaction is a process that leads to the transformation of one set of chemical substances to another.[1] Classically, chemical reactions encompass changes that only involve the positions of electrons in the forming and breaking of chemical bonds between atoms, with no change to the nuclei (no change to the elements present), and can often be described by a chemical equation. Nuclear chemistry is a sub-discipline of chemistry that involves the chemical reactions of unstable and radioactive elements where both electronic and nuclear changes can occur. As an ABCOM Student we can apply this significance in our daily life because we gather different reaction in very different situation.

Mary Grace Gonzales on February 24, 2017:

BU BSTM 4A chemical reaction equation gives the reactants and products, and a balanced chemical reaction equation shows the mole relationships of reactants and products. Often, the amount of energy involved in the reaction is given. Dealing with the quantitative aspect of chemical reactions is called reaction stoichiometry. Sci 202

Rayco, Samantha Aiva Mareey S. - BS PSY II (GenChem/ TF / 7:30-12:00) on February 23, 2017:

Reactions occur when two or more molecules interact and the molecules change. Bonds between atoms are broken and created to form new molecules. Chemical reaction, a process in which one or more substances, the reactants, are converted to one or more different substances, the products. Substances are either chemical elements or compounds. A chemical reaction rearranges the constituent atoms of the reactants to create different substances as products. It is an integral part of technology, of culture, and indeed of life itself. Burning fuels, smelting iron, making glass and pottery, brewing beer, and making wine and cheese are among many examples of activities incorporating chemical reactions that have been known and used for thousands of years. Chemical reactions abound in the geology of Earth, in the atmosphere and oceans, and in a vast array of complicated processes that occur in all living systems. When making a new substance from other substances, chemists say either that they carry out a synthesis or that they synthesize the new material. Reactants are converted to products, and the process is symbolized by a chemical equation.

AZ08 on February 22, 2017:

Eimeren Grace DC. Soriaga (BS-PSYII)

It is important to balance chemical equations because there must be an equal number of atoms on both sides of the equation to follow the Law of the Conservation of Mass. This chemical law states that in order for the equation to be correct, "An equal quantity of matter exists both before and after the experiment; the quality and quantity of the elements remain precisely the same." For example, if you want to make your car run, or make a plant grow, or made a baking soda - vinegar volcano, you'll need to perform a chemical reaction. Unless something involves only the movement of energy from one place to another, it has to involve chemistry.

Zipagan on February 22, 2017:

Dhaina Marie B. Zipagan (BAC-II)

The substance (or substances) initially involved in a chemical reaction are called reactants or reagents. A reagent a substance or compound added to a system to cause a chemical reaction, or added to see if a reaction occurs.The terms reactant and reagent are often used interchangeably, however, a reactant is more specifically a substance consumed in the course of a chemical reaction. A chemical reaction is a process that leads to the transformation of one set of chemical substances to another. Classically, chemical reactions encompass changes that only involve the positions of electrons in the forming and breaking of chemical bonds between atoms, with no change to the nuclei (no change to the elements present), and can often be described by a chemical equation.

There are different chemical reactions happening around us and even inside our bodies like digestion of food in the stomach, the process of breathing in the man's lungs, photosynthesis of food components in living cells, baking brownies, rusting of iron and combustion.

Nik Miranda on February 22, 2017:

Miranda, Nixieline

BAC-II

Chemical reaction, a process in which one or more substances, the reactants, are converted to one or more different substances, the products. Substances are either chemical elements or compounds. A chemical reaction rearranges the constituent atoms of the reactants to create different substances as products.Chemical reactions are an integral part of technology, of culture, and indeed of life itself. Burning fuels, smelting iron, making glass and pottery, brewing beer, and making wine and cheese are among many examples of activities incorporating chemical reactions that have been known and used for thousands of years. Chemical reactions abound in the geology of Earth, in the atmosphere and oceans, and in a vast array of complicated processes that occur in all living systems.

Frances Birco on February 22, 2017:

Frances Birco

(BAC-II)

Stoichiometry measures quantitative relationships and it is used to determine the amount of products or reactants that are produced or needed in a given reaction. It is also described as quantitative relationships among substances as they participate in chemical reactions. In relation to Mass Communication, we deal with the public on how they will react to our product of information we have collected and filtered to come up with an informative news.

Nikki Villaroman on January 27, 2017:

Villaroman Nikki D.C. BEED III

T/F BSC206b cas 105 12:30-2:00

Chemical reaction, a process in which one or more substances, the reactants, are converted to one or more different substances, the products. Substances are either chemical elements or compounds. A chemical reaction rearranges the constituent atoms of the reactants to create different substances as products. As a future educator making the students know about chemical reaction would help them to understand of how or why certain things happen and could use it ti their advantage.

mariseperez08 on January 23, 2017:

Niña Marise V. Perez

BEED-II

BSC206b (Inorganic Chemistry)

TF-12:30-2:00pm/CS105

All materials are made of chemicals. Chemical reactions involve interaction between chemicals such that all reactants are changed into new materials. Chemical reactions involve breaking chemical bonds between reactant molecules (particles) and forming new bonds between atoms in product particles. Chemical reactions happen at a characteristic reaction rate at a given temperature and chemical concentration. Typically, reaction rates increase with increasing temperature because there is more thermal energy available to reach the activation energy necessary for breaking bonds between atoms. A chemical equation is a type of relation you will encounter every day in chemistry. Here's a look at what a chemical equation is and some examples of chemical equations. A chemical equation is a written representation of the process that occurs in a chemical reaction. A chemical equation is written with the reactants on the left side of an arrow and the products of the chemical reaction on the right side of the equation.

Ma. Luz C. Mendoza (BEED II) on January 23, 2017:

Ma. Luz Mendoza (BEED II)

All materials are made of chemicals. Chemical reactions involve interaction between chemicals such that all reactants are changed into new materials. The properties of the new materials are different from those of the reactants. This is distinct from other changes such as evaporation, melting, boiling, freezing and mixing where changes involve no new substances. While heat is often necessary to start reactions, this need not be the case. Chemical reactions involve breaking chemical bondsbetween reactant molecules (particles) and forming new bonds between atoms in product particles (molecules). The number of atoms before and after the chemical change is the same but the number of molecules will change. Although many chemical reactions proceed quickly, small, slow changes such as rusting or biological processes can take place over much longer periods of time. Chemical reactions are reversible (a fact often omitted in many science texts) but in practice most differ from other changes children observe, such as melting, by being very difficult to reverse. Humans use chemical reactions to produce a wide range of useful materials; the breakdown of waste materials also involves chemical reactions that occur naturally in the environment. For some human made wastes, there are no such reactions and they cause problems as a result. As a future teacher, teaching about chemical reactions at this level the emphasis should be on improving student understanding of the importance of chemical reactions in our lives.

Villaroman on January 22, 2017:

Villaroman Nikki D.C. BEED III

BSC206b (T/F 12:30-2:00/CS 105)

Chemical reaction, a process in which one or more substances, the reactants, are converted to one or more different substances, the products. Substances are either chemical elements or compounds. A chemical reaction rearranges the constituent atoms of the reactants to create different substances as products. As a future educator making the students know about chemical reaction would help them to understand of how or why certain things happen and could use it ti their advantage.

JosephineLopez04 on January 21, 2017:

Chemical Reaction is a process that involves rearrangement of the molecular or ionic structure of a substance, as opposed to a change in physical form or a nuclear reaction. Some examples are: Soaps and detergents clean by way of chemical reactions, Thousand of chemical reaction take place during digestion of our body, Mixing or Combining different Ingredients when cooking and more. A chemical equation is a type of relation you will encounter every day in chemistry. It is the symbolic representation of a chemical reaction in the form of symbols and formulae, wherein the reactant entities are given on the left-hand side and the product entities on the right-hand side.The coefficients next to the symbols and formulae of entities are the absolute values of the stoichiometric numbers.

Elize Bantang 14 on January 21, 2017:

Merle, Eliza B.

BEEd-ll

BSC 206 Inorganic Chemistry TF 12:30-2:00

A chemical reaction is all about chemical change . Examples: ripening of fruits, photosynthesis, tarnishing of iron, burning of woods, digestion of foods and even cooking. A chemical reaction involves the transformation of one or more substances into another substance/s. It involves a change in composition and is represented by a chemical equation. Chemical equation provides a concise picture of a chemical change. It is used to convey the pertinent information about the chemical reaction which includes the substances involved and their quantitative ratio. Chemical equations are representations of chemical reactions in terms of symbols of elements and formulas of compounds. Reactants are the substances that enter inti a chemical reaction and the products are the substances formed. In relation to my course, "teaching can change the lives of the students". As a future elementary teacher. I want to motivate and inspire my pupils to study hard and do good to others by giving them a quality teaching that they can use to Change the World.

Cristina Perez on January 21, 2017:

Perez, Ma. Cristina M. (BEED-II)

A chemical reaction is the change of a substance into a new one that has a different chemical identity. A chemical reaction is usually accompanied by easily observed physical effects, such as the emission of heat and light, the formation of a precipitate, the evolution of gas, or a color change. Absolute confirmation of a chemical change can only be validated by chemical analysis of the products. Chemical reactions help us understand the properties of matter. It is important to balance chemical equations because there must be an equal number of atoms on both sides of the equation to follow the Law of the Conservation of Mass. This chemical law states that in order for the equation to be correct, "An equal quantity of matter exists both before and after the experiment; the quality and quantity of the elements remain precisely the same." In the field of teaching, teachers must possess good doings because students tend to imitate their teachers. Teachers can be similar to chemical reaction because they might change the lives of their students. They let their student's lives transform into new beginning.

Carmela Perez on January 21, 2017:

Perez, Ma. Carmela M.

(BEED-II)

BSC 206B (Inorganic Chemistry/ TF/ 12:30-2:00/ CS 105)

A chemical reaction is a process in which one set of chemical substances (reactants) is converted into another (products). It involves making and breaking chemical bonds and the rearrangement of atoms. Chemical reactions are represented by balanced chemical equations, with chemical formulas symbolizing reactants and products while chemical equations give information in two major areas: first, they tell us what substances are reacting (those being used up) and what substances are products (those being made). Second, the coefficients of a balanced equation tell us in what ratio the substances react or are produced. Chemical reactions has to do with teaching in metaphoric way. Teaching is inspiring your students to achieve their goals and aspirations in life. The role of a teacher is to be an inspiration to everyone; that we need to touch the lives of our students and be responsible for what they will become in the future. Chemical reactions and teaching goes hand and hand as they show that once there is something added on one thing it guarantees that there is a great change.

Salvador, Jucel Roma M. on January 21, 2017:

BEED-II

BSC 206B (Inorganic Chemistry/ TF/ 12:30-2:00/ CS 105)

A reaction is how chemical change occurs. A chemical reaction occur when matter interacts with other matter to make new products. It helps us understand the properties of matter. By studying the way a sample interacts with other matter, we can learn its chemical properties. While chemical equation is an expression of a chemical process that uses symbols and formulas instead of words to describe the changes. Reactants are the substances that combine in the reaction and products are the substances that are formed by the reaction. In balancing chemical equations, we have to consider a lot of rules. It is essentially done by trial and error because there are a lot of ways and systems of doing this. But it is important to count the number of atoms in an equation.

Maryn Pineda BAC-II on January 13, 2017:

In this part of chemistry I have learned how to read properly the names of the chemical bonds.

This learning can be used for my course for Communication should only tell facts. And this is facts.

Chella Maniquiz BSTM 7:30-12:00 TF on January 10, 2017:

Chemical reaction helps us to understand the properties of matter. It explains how the natural world works. All the substances in daily life are the result of chemical change. Therefor, without chemical reactions, nothing would ever change and no organism could live.

Vivian Jane M. Mempin on January 08, 2017:

Vivian Jane M. Mempin

BAC-II

Gen.Chem (TF/7:30-12:00/CS301)

Chemical reaction takes place when one or more substances transforms into new or another substance or substances. It involves combining or mixing two or more elements to form new product/s. Here, we will apply the rules in balancing chemical equations. Chemical reactions go hand in hand with chemical change and this is represented by chemical equations. There's also a need to know the factor which may affect the rates in which the reaction will take place, such as the nature of reactants, concentration of reactants, temperature, and catalyst. All of these are important for an experiment to be successful. Mere curiosity is not enough, we always have to follow the right procedures in order to achieve the desired result or product.

Within the reach of my course, AB Communication, simple ideas may be transformed into brilliant works through the writer's creative imagination and proper use of words. To deliver good news reports, a simple research will be done, and it will undergo many process until it airs in national television. The factors that we have to consider here are the communication skills of the reporter, availability of data, the channel or medium's availability, and the level of knowledge of the reporter , plus some environmental factors like signal disruption and disasters.

Shara Mae T. Rivera BSHM 4-1 (7:30-12:00) on January 07, 2017:

Chemistry happens in the world around you, not just in a lab. Matter interacts to form new products through a process called a chemical reaction or chemical change. Every time you cook or clean, it's chemistry in action. Your body lives and grows thanks to chemical reactions. There are reactions when you take medications, light a match, and take a breath. Here's a look at 10 chemical reactions in everyday life.

John Ismael Espino Lozano from Baliuag Bulacan Philippines on December 19, 2015:

Lozano, John Ismael E. (BSA 1-2)

According to what I have read, cell physiology is the physical process and activities of cell in our body (even in other organisms).it is the reason why all living organisms maintain their lives on their life span. It is the most important of all about cells because it includes the important process of cells (Membrane Transport, Photosynthesis, Protein Synthesis, Cell Division, and cellular Respiration) that essential to us to be learned.

Angelica Salinas on November 25, 2015:

Angelica G. Salinas

BSBA 1-1

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A chemical reaction is a process that leads to the transformation of one set of chemical substances to another. The substance (or substances) initially involved in a chemical reaction are called reactants or reagents. Chemical reactions are usually characterized by a chemical change, and they yield one or more products, which usually have properties different from the reactants. Chemical reactions are described with chemical equations, which symbolically present the starting materials, end products, and sometimes intermediate products and reaction conditions. Chemical equations are used to graphically illustrate chemical reactions. They consist of chemical or structural formulas of the reactants on the left and those of the products on the right. They are separated by an arrow (→) which indicates the direction and type of the reaction; the arrow is read as the word "yields".