Section 1.5 Chemical Equations

Question 1

What are the components of a chemical reaction?

Answer 1

Reactants (the substances you start with) and the products (the new substances made)

Can be a word or symbol equation

Has an arrow to represent the reactants forming the products (never use equals sign)

Question 2

What is a chemical reaction?

Answer 2

In a chemical reaction, the atoms get rearranged but are never destroyed or created

Question 3

What does an equation being balanced mean?

Answer 3

When there is the same number of each types of atom on both sides of the equation. This is because the total mass of the products formed in a reaction is equal to the total mass of the reactants (because atoms are not destroyed or created)

Question 4

What are state symbols?

Answer 4

State symbols show the state of the compound/element:

(s) for solid
(l) for liquid
(g) for gases
(aq) for substances dissolved in water or aqueous solutions

Question 5

Balance this equation:

H2 + O2 → H2O

Answer 5

2H2 + O2 → 2H2O

Question 6

Balance this equation:

KNO3 → KNO2 +O2

Answer 6

2KNO3 → 2KNO2 + O2

Question 7

Balance this equation:

Li + O2 → Li2O

Answer 7

4Li + O2 → 2Li2O

Question 8

Balance this equation:

Fe + O2 → Fe2O3

Answer 8

4Fe + 3O2 → 2Fe2O3