Question 1

Which of the following best describes a chemical change?

Accepted Answer

A piece of iron rusting when left outside.

Question 2

A sample of gas occupies 2.50 L at a pressure of 1.00 atm and a temperature of 300 K. What will the volume be if the pressure is increased to 2.00 atm and the temperature is decreased to 200 K? (Use the combined gas law: $$\frac{P_1$ V_1$}{T_1$} = \frac{P_2$ V_2$}{T_2$})$$

Accepted Answer

$$V_2 = 0.83$$\ \mathrm{L}$$

Question 3

Which of the following statements about intermolecular forces is correct?

Accepted Answer

Dispersion forces are present in all substances, but are the only forces in nonpolar molecules.

Question 4

A 50.0 g sample of water is heated from $$25.0\ ^\circ\mathrm{C} to$$ $$75.0\ ^\circ\mathrm{C}. If $$the specific heat capacity of water is $$4.18\ \mathrm{J/g\cdot ^\circ C}$$, how much energy is absorbed?

Accepted Answer

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

Question 5

Which of the following best explains why salt is used to melt ice on roads in winter?

Accepted Answer

Salt decreases the freezing point of water, causing ice to melt at lower temperatures.

Question 6

A reaction has a theoretical yield of 10.0 g, but only 7.5 g of product is actually obtained. What is the percent yield?

Accepted Answer

$$75\%$$

Question 7

Which of the following is a homogeneous mixture?

Accepted Answer

A glass of salt water.

Question 8

Which law explains why a balloon shrinks when placed in a freezer?

Accepted Answer

Charles's Law: $$\frac{V_1$}{T_1$} = \frac{V_2$}{T_2$}$$

Question 9

Which of the following best describes the difference between an element and a compound?

Accepted Answer

A compound consists of two or more elements chemically combined in a fixed ratio.

Question 10

A 0.500 mol sample of an ideal gas is at a pressure of 1.00 atm and a temperature of $$273\ \mathrm{K}. $$What is its volume? (Use $$R = 0.0821\ \mathrm{L\cdot atm/(mol\cdot K)}$$ and $$PV = nRT.)$$

Accepted Answer

$$V = 11.2\ \mathrm{L}$$

Question 11

Which of the following statements about energy is correct?

Accepted Answer

The total energy of the universe is constant; energy can only be converted from one form to another.

Question 12

A solution is prepared by dissolving 10.0 g of NaCl in 90.0 g of water. What is the mass percent of NaCl in the solution?

Accepted Answer

$$10\%$$

Question 13

Which of the following best explains why water has a higher boiling point than methane ($$\mathrm{CH_4$}$$)?

Accepted Answer

Water forms hydrogen bonds, which are stronger than the dispersion forces in methane.

Question 14

A 250 mL sample of a 2.00 M NaCl solution is diluted to a final volume of 1.00 L. What is the new concentration?

Accepted Answer

$$0.50\ \mathrm{M}$$

Question 15

Which of the following is an example of a physical property?

Accepted Answer

The boiling point of ethanol is $$78.4\ ^\circ\mathrm{C}.$$

Question 16

A reaction mixture contains 5.0 g of A and 10.0 g of B. The reaction is $$A + 2B \rightarrow C. If $$the molar masses are $$A = 10.0\ \mathrm{g/mol}$$ and $$B = 5.0\ \mathrm{g/mol}$$, what is the limiting reactant?

Accepted Answer

A

Question 17

Which of the following best describes osmosis?

Accepted Answer

The movement of solvent molecules from low to high solute concentration through a semipermeable membrane.

Question 18

Which of the following statements about gases is true according to the kinetic molecular theory?

Accepted Answer

Gas particles are in constant, random motion and have negligible volume compared to the container.

Question 19

A solution is made by dissolving 0.10 mol of glucose ($$\mathrm{C_6H_{12}O_6$}) in 1.00 kg of $$water. If the freezing point depression constant for water is $$K_f = 1.86\ ^\circ\mathrm{C\cdot kg/mol}$$, what is the expected freezing point of the solution? (Freezing point of pure water is $$0.00\ ^\circ\mathrm{C}.)$$

Accepted Answer

$$-0.37\ ^\circ\mathrm{C}$$

Question 20

Which of the following best describes the process of collecting a gas over water in a laboratory?

Accepted Answer

The total pressure measured is the sum of the gas pressure and the vapor pressure of water.

Introductory Chemistry: Study Guide for Matter, Energy, Gases, Liquids, Solids, and Solutions

Guida di studio - Domande di pratica

Study guide - Flashcard