Question 1

A student measures the mass of a sample three times and records the following values: 2.51 g, 2.50 g, and 2.52 g. The true mass is 2.80 g. Which statement best describes the accuracy and precision of these measurements?

Accepted Answer

The measurements are precise but not accurate.

Question 2

How many significant figures are in the measurement 0.0045600 g?

Accepted Answer

6

Question 3

Round the number 0.0067891 to three significant figures.

Accepted Answer

0.00679

Question 4

Express 4,520,000 in scientific notation with three significant figures.

Accepted Answer

$$4.52 	imes 10^6$

Question 5

Calculate the result of $$3.24 	imes 1.1$$ and express your answer with the correct number of significant figures.

Accepted Answer

$$3.6$$

Question 6

A sample of water has a mass of 250.0 g and a volume of 245 mL. What is the density of the water, reported with the correct number of significant figures?

Accepted Answer

$$1.02\ \mathrm{g/mL}$$

Question 7

Convert 0.250 kilometers to centimeters.

Accepted Answer

$$25,000\ \mathrm{cm}$$

Question 8

Which of the following is a chemical change?

Accepted Answer

Burning wood

Question 9

Which of the following is a homogeneous mixture?

Accepted Answer

Salt water

Question 10

Which statement best describes the difference between a pure substance and a mixture?

Accepted Answer

A pure substance has a fixed composition, while a mixture does not.

Question 11

Which of the following best describes the properties of a gas?

Accepted Answer

Indefinite shape and indefinite volume

Question 12

Which of the following substances would you expect to have the strongest intermolecular forces?

Accepted Answer

Water ($$H_2O)$$

Question 13

Convert 25.0 $$^\circC to $$Kelvin.

Accepted Answer

$$298.2\ \mathrm{K}$$

Question 14

Which of the following processes is exothermic?

Accepted Answer

Combustion of gasoline

Question 15

A gas occupies 2.00 L at 1.00 atm. If the pressure is increased to 4.00 atm at constant temperature, what is the new volume of the gas?

Accepted Answer

$$0.50\ \mathrm{L}$$

Question 16

A sample of gas at 300 K and 2.00 atm has a volume of 5.00 L. If the temperature is increased to 600 K and the pressure is decreased to 1.00 atm, what is the new volume?

Accepted Answer

$$20.0\ \mathrm{L}$$

Question 17

Which of the following is an example of a heterogeneous mixture?

Accepted Answer

Salad dressing with oil and vinegar

Question 18

A student adds 10.0 mL of ethanol (density = $$0.789\ \mathrm{g/mL}) to 20.0 mL of $$water (density = $$1.00\ \mathrm{g/mL}). $$What is the total mass of the mixture?

Accepted Answer

$$27.9\ \mathrm{g}$$

Question 19

Which of the following best explains why gases are compressible while solids are not?

Accepted Answer

Gas particles are much farther apart than solid particles.

Question 20

A beaker contains a mixture of sand and salt. Which method would best separate the two substances?

Accepted Answer

Filtration

CHEM 100 Exam I Study Guide: Foundations of Chemistry

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