Question 1

Which of the following best describes the difference between an empirical formula and a molecular formula?

Accepted Answer

An empirical formula shows the simplest whole-number ratio of the elements in a compound, while a molecular formula shows the actual number of atoms of each element in a molecule.

Question 2

A student measures the mass of a liquid as $$12.34\ \mathrm{g}$$ and its volume as $$8.2\ \mathrm{mL}. $$What is the density of the liquid, reported with the correct number of significant figures?

Accepted Answer

$$1.50\ \mathrm{g/mL}$$

Question 3

Which of the following statements about laboratory safety is CORRECT according to the course syllabus?

Accepted Answer

Safety goggles and lab coats must be worn at all times in the lab.

Question 4

Which of the following is the correct balanced 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 5

A sample contains $$3.01 	imes 10$$^{23}$$ molecules of water. How many moles of water does this represent?

Accepted Answer

$$0.50$$ moles

Question 6

Which of the following best explains why ionic compounds tend to have high melting points?

Accepted Answer

They are composed of ions held together by strong electrostatic forces.

Question 7

A gas occupies $$2.50\ \mathrm{L} at$$ $$1.00\ \mathrm{atm}$$ and $$300\ \mathrm{K}. $$What volume will it occupy at $$2.00\ \mathrm{atm}$$ and $$300\ \mathrm{K}$$, assuming ideal behavior?

Accepted Answer

$$1.25\ \mathrm{L}$$

Question 8

Which of the following is the correct Lewis structure for carbon dioxide ($$\mathrm{CO_2$}$$)?

Accepted Answer

O=C=O, with each oxygen atom having two lone pairs

Question 9

A solution is prepared by dissolving $$5.00\ \mathrm{g} of $$NaCl in enough water to make $$250.0\ \mathrm{mL} of $$solution. What is the molarity of the solution? ($$\mathrm{NaCl}$$ molar mass = $$58.44\ \mathrm{g/mol})$$

Accepted Answer

$$0.342\ \mathrm{M}$$

Question 10

Which of the following statements about acids and bases is TRUE according to the Bronsted-Lowry theory?

Accepted Answer

An acid is a substance that donates a proton ($$\mathrm{H^+}$$), and a base is a substance that accepts a proton.

Question 11

A student mixes solutions of silver nitrate ($$\mathrm{$$AgNO_3$$}) $$and sodium chloride ($$\mathrm{NaCl}). A $$white precipitate forms. What is the net ionic equation for this reaction?

Accepted Answer

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

Question 12

Which of the following best describes Le Chatelier’s Principle?

Accepted Answer

If a system at equilibrium is disturbed, the system will shift to minimize the disturbance and re-establish equilibrium.

Question 13

Which of the following is the correct equilibrium constant expression for the reaction $$\mathrm{N_2$} (g) + 3\mathrm{H_2$} (g) \rightleftharpoons 2\mathrm{NH_3$} (g)$$?

Accepted Answer

$$K = \dfrac{[\mathrm{NH_3$}]^2}{[\mathrm{N_2$}][\mathrm{H_2$}]^3}$$

Question 14

A sample of gas at $$27^\circ \mathrm{C}$$ and $$1.00\ \mathrm{atm}$$ has a volume of $$10.0\ \mathrm{L}. $$What will the volume be at $$127^\circ \mathrm{C}$$ and $$1.00\ \mathrm{atm}$$?

Accepted Answer

$$13.4\ \mathrm{L}$$

Question 15

Which of the following is a correct statement about oxidation numbers?

Accepted Answer

The oxidation number of oxygen in peroxides is $$-1.$$

Question 16

A student needs to prepare $$100.0\ \mathrm{mL} of$$ $$0.250\ \mathrm{M}$$ $$\mathrm{H_2SO_4}$$ from a $$1.00\ \mathrm{M}$$ stock solution. What volume of the stock solution should be used?

Accepted Answer

$$25.0\ \mathrm{mL}$$

Question 17

Which of the following best describes the trend in atomic radius across a period in the periodic table?

Accepted Answer

Atomic radius decreases from left to right across a period.

Question 18

A solution has a pH of $$3.0. $$What is the concentration of $$\mathrm{H_3O^+} in $$the solution?

Accepted Answer

$$1.0 	imes 10$$^{-3}$$\ \mathrm{M}$$

Question 19

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

Accepted Answer

The total mass of reactants equals the total mass of products in a chemical reaction.

Chem 170 Introductory Chemistry Syllabus and Study Guide

Guida di studio - Domande di pratica

Study guide - Flashcard