Q: Convert 0.0250 km to centimeters using dimensional analysis.

$$0.0250 \times 10^5$ = 2,500 cm$$

Q: A sample of ethanol has a density of $$0.789 \ \mathrm{g/mL}. $$What is the mass of $$50.0 \ \mathrm{mL} of $$ethanol?

$$0.789 \times 50.0 = 39.5 \ \mathrm{g}$$

Q: A metal sample with a mass of $$100.0 \ \mathrm{g} is $$heated from $$25.0^\circ \mathrm{C} to$$ $$75.0^\circ \mathrm{C}$$, absorbing $$2,000 \ \mathrm{J} of $$heat. What is the specific heat capacity $$c of $$the metal? Use $$q = m \cdot c \cdot \Delta T.$$

$$c = \frac{2,000}{100.0 \times 50.0} = 0.40 \ \mathrm{J/g}^\circ \mathrm{C}$$

Question 1

Which of the following best describes a scientific law?

Accepted Answer

A summary of observed behavior that applies to a wide range of situations and is always true under the same conditions.

Question 2

A student measures the mass of a sample as 12.34 g and its volume as 4.56 mL. What is the density of the sample, and how many significant figures should the answer have?

Accepted Answer

2.71 g/mL, 3 significant figures (rounded from 2.706)

Question 3

Which of the following is an example of a chemical change?

Accepted Answer

Iron rusting in moist air

Question 4

Convert 0.0250 km to centimeters using dimensional analysis.

Accepted Answer

$$0.0250 	imes 10^5$ = 2,500 cm$$

Question 5

Which of the following statements about the law of conservation of mass is correct?

Accepted Answer

The total mass of reactants equals the total mass of products in a closed system.

Question 6

A sample of ethanol has a density of $$0.789 \ \mathrm{g/mL}. $$What is the mass of $$50.0 \ \mathrm{mL} of $$ethanol?

Accepted Answer

$$0.789 	imes 50.0 = 39.5 \ \mathrm{g}$$

Question 7

Which of the following is a heterogeneous mixture?

Accepted Answer

Sand and iron filings

Question 8

A reaction absorbs heat from the surroundings and causes the temperature of the surroundings to decrease. This reaction is:

Accepted Answer

Endothermic

Question 9

Which of the following is the correct SI unit for measuring energy?

Accepted Answer

Joule (J)

Question 10

A metal sample with a mass of $$100.0 \ \mathrm{g} is $$heated from $$25.0^\circ \mathrm{C} to$$ $$75.0^\circ \mathrm{C}$$, absorbing $$2,000 \ \mathrm{J} of $$heat. What is the specific heat capacity $$c of $$the metal? Use $$q = m \cdot c \cdot \Delta T.$$

Accepted Answer

$$c = \frac{2,000}{100.0 	imes 50.0} = 0.40 \ \mathrm{J/g}^\circ \mathrm{C}$$

Question 11

Which of the following best describes potential energy?

Accepted Answer

Energy stored due to position or composition

Question 12

Convert $$37.0^\circ \mathrm{C} ($$normal human body temperature) to Kelvin.

Accepted Answer

$$37.0 + 273.15 = 310.15 \ \mathrm{K}$$

Question 13

Which of the following is a physical property?

Accepted Answer

Density

Question 14

A student records the following measurements: 2.50 m, 2.5 m, and 2.500 m. Which statement is correct regarding significant figures?

Accepted Answer

2.5 m has 2 significant figures; 2.50 m has 3; 2.500 m has 4.

Question 15

Which of the following is an example of an amorphous solid?

Accepted Answer

Glass

Question 16

A solution is prepared by dissolving 10.0 g of NaCl in 100.0 g of water. Which classification best describes this mixture?

Accepted Answer

Homogeneous mixture

Question 17

Which of the following is the correct prefix for $$10^{-3}$$?

Accepted Answer

Milli-

Question 18

A car engine converts chemical energy from gasoline into kinetic energy and heat. Which law does this illustrate?

Accepted Answer

Law of conservation of energy

Question 19

Which of the following is the correct formula for calculating heat energy absorbed or released by a substance?

Accepted Answer

$$q = m \cdot c \cdot \Delta T$$

Introductory Chemistry Study Guide: Chapters 1–3

Guida di studio - Domande di pratica

Study guide - Flashcard