Question 1

Which of the following is NOT a sign that a chemical reaction has occurred?

Accepted Answer

Dissolving sugar in water

Question 2

Which symbol in a chemical equation indicates that a substance is dissolved in water?

Accepted Answer

$$(aq)$$

Question 3

Which of the following elements is DIATOMIC in its natural state?

Accepted Answer

Oxygen

Question 4

What is the balanced chemical equation for the combustion of charcoal (carbon) in oxygen to form carbon dioxide?

Accepted Answer

$$C(s) + O_2$(g) \rightarrow CO_2$(g)$$

Question 5

According to the law of conservation of mass, which statement is TRUE for a balanced chemical equation?

Accepted Answer

The number of atoms of each element is the same on both sides of the equation

Question 6

Balance the following equation: $$2Al(s) + 3CuCl_2(aq) \rightarrow 2AlCl_3(aq) + 3Cu(s). $$What is the coefficient for $$CuCl_2$$?

Accepted Answer

3

Question 7

Which of the following best describes the role of coefficients in a balanced chemical equation?

Accepted Answer

They show the number of molecules or moles involved in the reaction

Question 8

A student writes the equation $$H_2(g$$) + $$O_2(g$$) \rightarrow H_2O(l)$$. What is wrong with this equation?

Accepted Answer

The equation is not balanced

Question 9

What is the balanced equation for the formation of water from hydrogen and oxygen?

Accepted Answer

$$2H_2(g) + O_2$(g) \rightarrow 2H_2O(l)$$

Question 10

Which of the following reactions demonstrates the formation of a precipitate?

Accepted Answer

Mixing silver nitrate and sodium chloride to form silver chloride

Question 11

Balance the following equation: $$C_3H_8 + O_2$ \rightarrow CO_2$ + H_2O. $$What is the correct set of coefficients?

Accepted Answer

$$1, 5, 3, 4$$

Question 12

Which statement about diatomic elements is correct?

Accepted Answer

They are found as molecules containing two atoms of the same element

Question 13

A chemical equation is balanced when:

Accepted Answer

The number of atoms of each element is the same on both sides

Question 14

Which of the following is a correct representation of a chemical reaction using state symbols?

Accepted Answer

$$NaCl(s) \rightarrow Na^+(aq) + Cl^-(aq)$$

Question 15

Which equation is correctly balanced for the reaction of sodium sulfate with calcium nitrate to produce sodium nitrate and calcium sulfate?

Accepted Answer

$$Na_2SO_4 + Ca(NO_3$)_2 \rightarrow 2NaNO_3 + $$CaSO_4$$

Question 16

Which of the following is a correct application of the law of conservation of mass in chemical reactions?

Accepted Answer

The total number of atoms of each element is conserved

Question 17

Balance the following equation: $$C_7H_{16} + O_2$ \rightarrow CO_2$ + H_2O. $$What is the coefficient for $$O_2$$?

Accepted Answer

11

Question 18

Which of the following best describes a chemical equation that is NOT balanced?

Accepted Answer

The number of atoms of at least one element is different on the reactant and product sides

Question 19

Which of the following is a correct balanced equation for the reaction: $$MgBr_2$$ + $$Cl_2$$ \rightarrow $$MgCl_2$$ + $$Br_2$$?

Accepted Answer

$$MgBr_2$$ + $$Cl_2$$ \rightarrow $$MgCl_2$$ + $$Br_2$$

Question 20

Which of the following is a multi-step process required to balance the equation: $$C_4H_{10} + O_2$ \rightarrow CO_2$ + H_2O$$?

Accepted Answer

Balance C atoms, then H atoms, then O atoms

Chemical Reactions: Evidence, Representation, and Balancing Chemical Equations

Study Guide - Practice Questions