Question 1

Which of the following best describes the law of conservation of mass as it applies to chemical equations?

Accepted Answer

The total number of atoms of each element must be the same on both sides of the equation.

Question 2

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

Accepted Answer

$$\mathrm{CH_4$} + 2\,\mathrm{O_2$} \rightarrow \mathrm{CO_2$} + 2\,\mathrm{H_2O}$$

Question 3

A student mixes aqueous solutions of $$\mathrm{Na_2SO_4}$$ and $$\mathrm{$$BaCl_2$$}. $$According to solubility rules, what will happen?

Accepted Answer

A precipitate of $$\mathrm{$$BaSO_4$$}$$ will form.

Question 4

Which of the following is the net ionic equation for the reaction between aqueous solutions of $$\mathrm{$$AgNO_3$$}$$ and $$\mathrm{NaCl}$$?

Accepted Answer

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

Question 5

Which of the following statements about redox reactions is TRUE?

Accepted Answer

Oxidation is the loss of electrons, and reduction is the gain of electrons.

Question 6

In the reaction $$\mathrm{Cu} (s) + 2\,\mathrm{Ag^+} (aq) \rightarrow \mathrm{Cu$$^{2+}$$} (aq) + 2\,\mathrm{Ag} (s)$$, which species is oxidized and which is reduced?

Accepted Answer

Cu is oxidized; Ag$$^+ is $$reduced.

Question 7

Which of the following is the correct net ionic equation for the neutralization of hydrochloric acid with sodium hydroxide?

Accepted Answer

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

Question 8

A sample of sodium chlorate ($$\mathrm{$$NaClO_3$$}) is $$heated and decomposes to form sodium chloride and oxygen gas. What is the balanced chemical equation for this reaction?

Accepted Answer

$$2\,\mathrm{$$NaClO_3$$} (s) \rightarrow 2\,\mathrm{NaCl} (s) + 3\,\mathrm{O_2$} (g)$$

Question 9

Which of the following compounds is most likely to be insoluble in water?

Accepted Answer

$$\mathrm{$$PbSO_4$$}$$

Question 10

What is the oxidation number of titanium in $$\mathrm{$$TiCl_4$$}$$?

Accepted Answer

+4

Question 11

Which of the following best describes a spectator ion?

Accepted Answer

An ion that does not participate in the chemical reaction and appears unchanged on both sides of the equation.

Question 12

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

Accepted Answer

$$\mathrm{2Al} (s) + 3\,\mathrm{Cl_2$} (g) \rightarrow 2\,\mathrm{$$AlCl_3$$} (s)$$

Question 13

Which of the following is the correct net ionic equation for the reaction of hydrochloric acid with sodium carbonate?

Accepted Answer

$$2\,\mathrm{H^+} (aq) + \mathrm{CO_3$^{2-}} (aq) \rightarrow \mathrm{H_2O} (l) + \mathrm{CO_2$} (g)$$

Question 14

Which of the following statements about oxidation numbers is correct?

Accepted Answer

The sum of the oxidation numbers in a neutral compound is zero.

Question 15

Which of the following best explains why alkali metals are strong reducing agents?

Accepted Answer

They have low ionization energies and readily lose electrons.

Question 16

A student is asked to balance the following equation: $$\mathrm{C_2H_6} + \mathrm{O_2$} \rightarrow \mathrm{CO_2$} + \mathrm{H_2O}. $$What is the correct set of coefficients (in order: $$\mathrm{C_2H_6}$$, $$\mathrm{O_2$}$$, $$\mathrm{CO_2$}$$, $$\mathrm{H_2O}$$)?

Accepted Answer

2, 7, 4, 6

Question 17

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

Accepted Answer

The rusting of iron in moist air

Question 18

In the reaction $$\mathrm{Fe_2O_3} + 3\,\mathrm{C} \rightarrow 2\,\mathrm{Fe} + 3\,\mathrm{CO_2$}$$, which reactant is the oxidizing agent?

Accepted Answer

$$\mathrm{Fe_2O_3}$$

Classification and Balancing of Chemical Reactions: Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard