Chemical Reactions Quiz

What is the purpose of balancing a chemical equation?

• To change the temperature of the reaction

• To ensure the law of conservation of mass is obeyed.

• To increase the reaction rate

• To create a new substance

Define reactants in a chemical reaction.

• Substances that inhibit a chemical reaction

• Substances that participate in a chemical reaction and are consumed to produce products.

• Substances that are produced in a chemical reaction

• Substances that have no role in a chemical reaction

Explain the concept of products in a chemical reaction.

• Products in a chemical reaction are not influenced by the reactants

• Products in a chemical reaction are always gases

• Products in a chemical reaction are the substances formed as a result of the reaction.

• Products in a chemical reaction are the starting materials

What are the symbols used in a chemical equation to represent different elements?

• Chemical symbols

• Atomic symbols

• Chemical codes

• Elemental signs

How do you balance the chemical equation: H2 + O2 -> H2O?

• H2 + O2 -> H2O2

• 2H2 + O2 -> 2H2O

• 2H2O -> 2H2 + O2

• H2O2 -> H2 + O2

In the chemical equation CH4 + 2O2 -> CO2 + 2H2O, identify the reactants and products.

• Reactants: CH4, 2O2; Products: CO2, 2H2O

• Reactants: CO2, 2H2O; Products: CH4, 2O2

• Reactants: H2O, CO2; Products: CH4, O2

• Reactants: CO2, 2H2O; Products: O2, CH4

What does the arrow in a chemical equation represent?

• Direction of the reaction

• Speed of the reaction

• Amount of reactants

• Temperature of the reaction

Balance the equation: Fe + O2 -> Fe2O3.

• Fe2O3 + O2 -> FeO2

• Fe + O2 -> Fe3O2

• 2Fe + 3O2 -> Fe2O3

• 4Fe + 3O2 -> 2Fe2O3

What happens to the total mass of reactants and products in a chemical reaction?

• The total mass of reactants is greater than the total mass of products.

• The total mass of reactants and products is unrelated in a chemical reaction.

• The total mass of reactants is less than the total mass of products.

• The total mass of reactants is equal to the total mass of products.

What is the law of conservation of mass in relation to chemical reactions?

• The law of conservation of mass states that mass can change into energy.

• The law of conservation of mass only applies to solid substances.

• In chemical reactions, the total mass of the reactants equals the total mass of the products.

• In chemical reactions, mass can be created or destroyed.