Question 1

Which of the following best describes the law of conservation of matter as it applies to a chemical reaction?

Accepted Answer

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

Question 2

A student measures the mass of a sample three times and records the values: 12.34 g, 12.3 g, and 12.345 g. According to the rules of significant figures, what is the correct way to report the average mass?

Accepted Answer

$$12.34\ \mathrm{g}$$

Question 3

Which of the following is the correct IUPAC name for $$\mathrm{Na_2SO_4}$$?

Accepted Answer

Sodium sulfate

Question 4

Which of the following statements about atomic structure is correct?

Accepted Answer

Protons and neutrons are found in the nucleus.

Question 5

A compound contains 40.0% carbon, 6.7% hydrogen, and 53.3% oxygen by mass. What is its empirical formula?

Accepted Answer

$$\mathrm{CH_2O}$$

Question 6

Which of the following best explains why water is a polar molecule?

Accepted Answer

Oxygen is more electronegative than hydrogen, and the molecule has a bent shape.

Question 7

A reaction between aqueous solutions of silver nitrate and sodium chloride produces a white precipitate. What is the net ionic equation for this reaction?

Accepted Answer

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

Question 8

Which of the following gases will effuse the fastest under identical conditions, according to Graham's law?

Accepted Answer

$$\mathrm{H_2$}$$

Question 9

A sample of gas occupies $$2.50\ \mathrm{L} at$$ $$1.00\ \mathrm{atm}$$ and $$25^\circ\mathrm{C}. $$What volume will it occupy at $$2.00\ \mathrm{atm}$$ and $$25^\circ\mathrm{C}$$?

Accepted Answer

$$1.25\ \mathrm{L}$$

Question 10

Which of the following is a redox reaction?

Accepted Answer

$$\mathrm{Zn(s) + $$CuSO_4$$(aq) \rightarrow $$ZnSO_4$$(aq) + Cu(s)}$$

Question 11

Which of the following statements about periodic trends is correct?

Accepted Answer

Ionization energy decreases down a group.

Question 12

Which of the following best describes the difference between an ionic and a covalent bond?

Accepted Answer

Ionic bonds involve the transfer of electrons, while covalent bonds involve the sharing of electrons.

Question 13

A $$10.0\ \mathrm{g}$$ sample of glucose ($$\mathrm{C_6H_{12}O_6$}) is $$combusted in a calorimeter. The temperature of $$500.0\ \mathrm{g} of $$water increases by $$5.00^\circ\mathrm{C}. $$What is the heat released, assuming all heat is absorbed by the water? ($$c = 4.18\ \mathrm{J/g\cdot ^\circ C})$$

Accepted Answer

$$10,450\ \mathrm{J}$$

Question 14

Which of the following is the correct electron configuration for a neutral phosphorus atom ($$Z=15$$)?

Accepted Answer

$$1s^2$$\ $$2s^2$$\ $$2p^6$$\ $$3s^2$$\ $$3p^3$$

Question 15

Which of the following molecules has a trigonal planar geometry?

Accepted Answer

$$\mathrm{BF_3$}$$

Question 16

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 17

Which of the following best describes the Bohr model of the atom?

Accepted Answer

Electrons occupy fixed orbits with quantized energies around the nucleus.

Question 18

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

Accepted Answer

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

Question 19

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

Accepted Answer

An acid is a proton donor and a base is a proton acceptor.

CHM 2045C Chemistry Fundamentals I: Course Structure, Topics, and Study Guide

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