Chemical Reactions

1. The breaking down of a compound into simpler substances is

Displacement

Synthesis

Decomposition

Endothermic

2. What does → signify?

"and"

"yields/produces"

Catalyst

Add heat

Submit

4. In an exothermic reaction, heat is

Absorbed

Released

Destroyed

Conserved

5. Numbers that precede (come before) symbols and formulas in a chemical equation are

Subscripts

Superscripts

Coefficients

Fractions

6. Each of the substances to the left of the arrow in a chemical equation is a

Catalyst

Product

Reactant

Coefficient

Submit

8. In a combustion reaction between a hydrocarbon and oxygen, the products are always?

A synthesis reaction

Carbon dioxide and water

Oxygen

Hydrogen, carbon and oxygen

9. Which of the following types of reactions results in a single product?

A synthesis reaction

A decomposition reaction

A combustion reaction

A single replacement reaction

A double replacement reaction

10. In a chemical reaction, the total mass of the substances before the reaction compared to the total mass of the substances after the reaction is

Usually smaller

Usually greater

Equal

Sometimes greater, sometimes smaller

11. What type of reaction is the following?
2KI + Pb(NO₃)₂ → PbI₂ + 2KNO₃

Synthesis

Decomposition

Single-replacement

Double-replacement

Combustion

12. What type of reaction is the following?
Cl₂ + 2NaBr → 2NaCl + Br₂

Synthesis

Decomposition

Single-replacement

Double-replacement

Combustion

13. In a double-replacement reaction

The reactants are usually one metal and one nonmetal

One of the reactants is often water

The reactants are generally two ionic compounds

Energy is always produced

14. What coefficients would be added to balance the following equation?
Fe + O₂ → Fe₂O₃

2, 3, 1

4, 3, 2

It is already balanced

You wouldn't add a coefficient you would just change the subscripts

15. Which of the following is a word equation?

Sodium oxide → sodium + oxygen

Sodium oxide decomposes to form sodium and oxygen

Na2O → Na + O2

2Na2O → 4Na + O2

16. An insoluble substance formed from two solutions is a

Reactant

Precipitate

Compound

Product

17. Which of the following is NOT an observable clue that a chemical reaction has occurred?

Release of a gas

Odor change

Precipitate formation

Mixing two reactants

18. In a combustion reaction, ______________ is always one of the reactants.

O

O2

CO2

H2O

19. Which compound would decompose to form Mg and O₂?

MgO2

MgO

Mg2O2

Mg and O2

20. What type of reaction is the following?
CH₄ + 2O₂ → CO₂ + 2H₂O

Synthesis

Decomposition

Single replacement

Double replacement

Combustion

21. In order for the reaction F₂ + NaCl → Cl₂ + NaF to occur, which of the following must be true?

F must be above Na on the activity series

F must be above Cl on the activity series

Na must be above F on the activity series

Cl must be above F on the activity series

22. What would be the products of the following decomposition reaction?
LiCl →

Li + Cl

LiCl

Li + Cl2

None of the above

23. What coefficients would balance the following equation?
Sr + H₂O → Sr(OH)₂ + H₂

1, 4, 2, 2

2, 4, 2, 4

1, 2, 1, 1

It is already balanced

24. Among the elements listed, which could replace all of the rest in a single replacement reaction?

Li

Mg

Cu

Ag

Ba