Question 1

Which of the following is NOT considered evidence of a chemical reaction?

Accepted Answer

Bubbles form when water boils.

Question 2

What is the balanced chemical equation for the combustion of methane ($$\mathrm{CH_4$}) in $$oxygen?

Accepted Answer

$$\mathrm{CH_4$(g) + 2 O_2$(g) \rightarrow CO_2$(g) + 2 H_2O(g)}$$

Question 3

Which of the following compounds is insoluble in water according to the solubility rules?

Accepted Answer

$$\mathrm{$$CuCO_3$$}$$

Question 4

What is the net ionic equation for the reaction between aqueous solutions of silver nitrate and sodium chloride?

Accepted Answer

$$\mathrm{Ag^+(aq) + Cl^-(aq) \rightarrow AgCl(s)}$$

Question 5

Which of the following best describes a combustion reaction?

Accepted Answer

A reaction in which a substance reacts with oxygen to form one or more oxygen-containing compounds, often releasing heat.

Question 6

Which of the following is a strong electrolyte in aqueous solution?

Accepted Answer

$$\mathrm{NaCl}$$

Question 7

What is the correct set of coefficients to balance the following equation: $$\mathrm{Al(s) + H_2SO_4(aq) \rightarrow Al_2$(SO_4$)_3(aq) + H_2$(g)}$$?

Accepted Answer

$$\mathrm{2, 3, 1, 3}$$

Question 8

Which of the following reactions is an example of a precipitation reaction?

Accepted Answer

$$\mathrm{2 KI(aq) + Pb(NO_3$)_2(aq) \rightarrow $$PbI_2$$(s) + 2 $$KNO_3$$(aq)}$$

Question 9

Which of the following is the correct molecular equation for the reaction between nitric acid and sodium carbonate?

Accepted Answer

$$\mathrm{2 $$HNO_3$$(aq) + Na_2CO_3(aq) \rightarrow H_2O(l) + CO_2$(g) + 2 $$NaNO_3$$(aq)}$$

Question 10

Which of the following is a redox (oxidation–reduction) reaction?

Accepted Answer

$$\mathrm{2 H_2$(g) + O_2$(g) \rightarrow 2 H_2O(g)}$$

Question 11

Which of the following best describes a synthesis reaction?

Accepted Answer

A reaction in which two simpler substances combine to form a more complex substance.

Question 12

Which of the following is the correct abbreviation for an aqueous solution in a chemical equation?

Accepted Answer

$$(aq)$$

Question 13

Which of the following is a correct net ionic equation for an acid–base neutralization reaction?

Accepted Answer

$$\mathrm{H^+(aq) + OH^-(aq) \rightarrow H_2O(l)}$$

Question 14

Which of the following statements about spectator ions is TRUE?

Accepted Answer

Spectator ions are present in the same form on both sides of a complete ionic equation.

Question 15

Which of the following is the correct sequence of steps for balancing a chemical equation?

Accepted Answer

Balance metals first, then nonmetals, then free elements.

Question 16

Which of the following is a real-world example of a gas evolution reaction?

Accepted Answer

Mixing baking soda (sodium bicarbonate) and vinegar (acetic acid) to produce carbon dioxide.

Question 17

Which of the following is a correct molecular equation for a precipitation reaction?

Accepted Answer

$$\mathrm{Na_2CO_3(aq) + $$CuCl_2$$(aq) \rightarrow $$CuCO_3$$(s) + 2 NaCl(aq)}$$

Chemical Reactions: Evidence, Equations, and Classifications

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