Grade 10 Science
April 22, 2024
CHEMICAL REACTION
In this module , you will further understand how a chemical change proceeds, how bonds are broken
and new bonds are formed, and how chemical reactions are translated into chemical equations, where
rearrangements of atoms causes the formation of new substance/s. A lot of these chemical changes made
the quality of our lives better.
Multiple Choice. Choose the correct answer.
1. During a chemical reaction,
a. atoms are destroyed
b. atoms are rearranged
c. elements are destroyed
d. new elements are produced
2. A chemical reaction is a process in which
a. all reactants change state
b. products change into reactants
c. the law of conservation of mass applies
d. all of these
3. What determines an atom’s ability to undergo chemical reactions?
a. protons
b. neutrons
c. innermost electrons
d. outermost electrons
4. How is a chemical equation is balanced?
a. changing subscripts
b. erasing elements as necessary
c. adding coefficients
d. adding elements as necessary
5. What are the products in the equation below?
Zn + CuSO4 -----> ZnSO4 + Cu
a. Zn and Cu
b. Zn and CuSO4
c. ZnSO4 and Cu
d. Zn only
6 -10 Write true if the statement is correct and false if incorrect, and change the underlined word/s to make
the statement correct.
6. Generally, the higher the concentration of the reacting substances, the faster is the reaction.
7. At lower temperature, chemical reactions occur at slower rates.
8. The bigger the surface area of the reactants, the faster the rate of reaction.
9. Catalysts increase the rate of reaction by providing a reaction pathway with a higher activation energy.
10. The minimum energy required to start a reaction is called bond energy.
IV. Reading Resources and Instructional Activities
KEY CONCEPTS:
When a physical change occurs there is no breaking and forming of bonds. There are certain things
that will help us identify if a chemical reaction has taken place. We call these evidences of chemical reactions.
1. Production of light
2. Evolution of gas
3. Temperature change
4. Change in intrinsic properties (color, odor)
5. Formation of precipitate
Oxygen is vital to life. One interesting reaction which involves oxygen is the production of fire.
Fire has fascinated people for so long, that the ancient people even regarded it as one of the earliest
elements. Fire was so important to them and they described it as an element that changes everything. The
earliest theory about burning was the Phlogiston Theory. This theory by George Ernst Stahl in the 17th century
stated that when a material burns, it releases a substance known as phlogiston, and this theory was accepted
for a very long time.
Antoine Lavoisier through his careful observations from his experiments, debunked the
phlogiston theory as he discovered that instead of releasing a substance (phlogiston) a
material accurately burns as it reacts (uses) with oxygen. This is now known as the Theory
of Oxidation, and this is accepted up to this day.
For burning to occur, 3 factors should be present in proper conditions and proportions.
1. Fuel
2. Oxygen
3. Heat
Grade 10 Science
April 23, 2024
A. Reactants and Products.
Reactants are substances that are used up to form new substances in a chemical reaction.
The following chemical reactions took place in Activity 1 procedure A to E.
1. Iron reacts with copper sulfate (CuSO4) and forms iron (II) sulphate (FeSO4) and copper.
2. Magnesium combines with oxygen gas (O2) to produce magnesium oxide
3. Hydrogen peroxide (H2O2) in the presence of manganese dioxide (MnO2) produces water and oxygen gas.
4. Acetic acid (CH3COOH) and sodium bicarbonate (NaHCO3) produce sodium acetate with the release of
carbon dioxide (CO2) gas and water.
5. Copper sulfate (CuSO4) reacts with sodium hydroxide (NaOH) to produce insoluble copper (II) hydroxide
Cu(OH)2 and sodium sulphate (Na2SO4 ) solution.
Fill in the table below with the Reactants and Products from the chemical reactions above. Below each
number, write the symbol or formula of the reactant and product.
Table 6. Reactants and Products
Reaction
Reactants
Products
1
Answer: Iron, Copper sulfate
Answer: Iron (II) sulphate, Copper
Fe, CuSO4
FeSO4, Cu
2
3
4
5
B. Symbols used in Chemical Equation
There are other symbols used in writing a chemical equations:
Using the symbols and formulas in Table 6 and the symbols in Table 7, write the chemical reaction
using these symbols to complete chemical equation.
Table 8. Chemical Reaction
Reaction
1
2
3
4
5
Chemical Equation
Grade 10 Science
April 24, 2024
ASSESSMENT
Classify the following unbalanced chemical equations according to the six types of chemical reactions.
A. Combination
B. Decomposition
C. Single displacement
D. Double displacement
E. Combustion
F. Acid-base
KEY CONCEPTS:
Law of Conservation of Mass states that mass is conserved in a chemical reaction. The total mass of
the reactants is equal to the total mass of the products. No new atoms are created or destroyed, there was
only grouping or regrouping (rearrangement) of atoms.
Steps in Balancing Equations:
Write the unbalanced chemical equation, make sure you have followed correctly the rules in writing
formulas of compounds.
• Take note of the elements present in the reactant and product side.
• Count the number of atom/s of each element present in the reactant and product side.
• Apply the Law of Conservation of Mass to get the same number of atoms of every element on each
side of the equation. Balance chemical equations by placing the appropriate coefficients before the
symbol or formula. Do not change the subscripts of the formula in an attempt to balance the equation
as it will change the identity of the components.
Let’s Practice!
Grade 10 Science
April 25, 2024
Writing Chemical Equations
Part A – Translate all the formulaic equations to word equations.
Part B – Translate all the word equations to formulaic equations and then balance them.
1.Sodium combines with chlorine to produce sodium chloride.
2. When solid copper reacts with aqueous silver nitrate, the products are aqueous copper II nitrate and
silver metal.
3. Solid iron III oxide and carbon monoxide gas produce iron metal and carbon dioxide gas.
4. Sulfuric acid and sodium hydroxide react to form sodium sulfate and water.
5. Vanadium II oxide with iron III oxide results in the formation of vanadium V oxide and iron II oxide.
6. Aluminum reacts with oxygen to produce aluminum oxide.
7. Mercury II oxide decomposes to produce mercury and oxygen
8. Sodium carbonate decomposes to produce sodium oxide and carbon dioxide
9. Carbon dioxide gas reacts with solid lithium hydroxide to produce solid lithium carbonate and water.
10. Ammonia gas reacts with oxygen gas to produce nitrogen monoxide gas and steam.
11. Solid ammonium nitrate decomposes to produce dinitrogen monoxide gas and water.
12. Carbon monoxide reacts with hydrogen to produce methanol.
13. Liquid carbon disulfide reacts with oxygen gas to produce carbon dioxide gas and sulfur dioxide gas.
14. Aluminum metal reacts with aqueous copper II chloride to produce aqueous aluminum chloride and
solid copper.
15. Solid ammonium chloride decomposes to produce ammonia gas and gaseous hydrochloric acid.