Q: A cube of gold has a length of $$2.00\ \mathrm{cm} on $$each side. If the density of gold is $$19.32\ \mathrm{g/cm^3$}$$, what is the mass of the cube?

$$\text{Mass} = (2.00\ \mathrm{cm})^3$ \times 19.32\ \mathrm{g/cm^3$} = 155\ \mathrm{g}$$

Q: A student measures the mass of a gas as $$1.38\ \mathrm{g}$$ and its volume as $$1.05 \times 10^3$\ \mathrm{cm^3$}. $$What is the density of the gas?

$$\text{Density} = \frac{1.38\ \mathrm{g}}{1.05 \times 10^3$\ \mathrm{cm^3$}} = 0.00131\ \mathrm{g/cm^3$}$$

Q: Which of the following is the correct conversion for $$115\ \mathrm{lb} to $$grams, using the conversion factor $$1\ \mathrm{lb} = 453.6\ \mathrm{g}$$?

$$115\ \mathrm{lb} \times \frac{453.6\ \mathrm{g}}{1\ \mathrm{lb}} = 5.22 \times 10^4$\ \mathrm{g}$$

Q: A student needs $$15.0\ \mathrm{g} of $$ethanol for an experiment. If the density of ethanol is $$0.789\ \mathrm{g/mL}$$, how many milliliters of ethanol are needed?

$$\text{Volume} = \frac{15.0\ \mathrm{g}}{0.789\ \mathrm{g/mL}} = 19.0\ \mathrm{mL}$$

Question 1

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

Accepted Answer

A compound has a definite composition, while a mixture can have variable composition.

Question 2

A student finds a clear, colorless liquid in the laboratory. The liquid boils at 100 °C and freezes at 0 °C. Which classification best fits this substance?

Accepted Answer

Compound

Question 3

Which of the following is an example of an intensive property?

Accepted Answer

Density

Question 4

Which separation technique would be most appropriate to separate a mixture of sand and salt water?

Accepted Answer

Filtration

Question 5

A weather forecaster predicts the temperature will reach 31 °C. What is this temperature in Kelvin?

Accepted Answer

$$K = 31 + 273.15 = 304.15\ \mathrm{K}$$

Question 6

Which of the following is a chemical property?

Accepted Answer

Flammability

Question 7

A cube of gold has a length of $$2.00\ \mathrm{cm} on $$each side. If the density of gold is $$19.32\ \mathrm{g/cm^3$}$$, what is the mass of the cube?

Accepted Answer

$$	ext{Mass} = (2.00\ \mathrm{cm})^3$ 	imes 19.32\ \mathrm{g/cm^3$} = 155\ \mathrm{g}$$

Question 8

Which of the following statements about significant figures is correct?

Accepted Answer

Zeros at the end of a number are significant if the number contains a decimal point.

Question 9

A student measures the mass of a gas as $$1.38\ \mathrm{g}$$ and its volume as $$1.05 	imes 10^3$\ \mathrm{cm^3$}. $$What is the density of the gas?

Accepted Answer

$$	ext{Density} = \frac{1.38\ \mathrm{g}}{1.05 	imes 10^3$\ \mathrm{cm^3$}} = 0.00131\ \mathrm{g/cm^3$}$$

Question 10

Which of the following best describes a homogeneous mixture?

Accepted Answer

A mixture with uniform composition throughout

Question 11

Which of the following is the correct conversion for $$115\ \mathrm{lb} to $$grams, using the conversion factor $$1\ \mathrm{lb} = 453.6\ \mathrm{g}$$?

Accepted Answer

$$115\ \mathrm{lb} 	imes \frac{453.6\ \mathrm{g}}{1\ \mathrm{lb}} = 5.22 	imes 10^4$\ \mathrm{g}$$

Question 12

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

Accepted Answer

Melting of ice

Question 13

A solution of salt water is heated until all the water evaporates, leaving salt behind. What type of change has occurred?

Accepted Answer

Physical change

Question 14

Which of the following best describes the Law of Constant Composition?

Accepted Answer

The relative number of atoms of each element in a compound is the same in any sample.

Question 15

A student needs $$15.0\ \mathrm{g} of $$ethanol for an experiment. If the density of ethanol is $$0.789\ \mathrm{g/mL}$$, how many milliliters of ethanol are needed?

Accepted Answer

$$	ext{Volume} = \frac{15.0\ \mathrm{g}}{0.789\ \mathrm{g/mL}} = 19.0\ \mathrm{mL}$$

Question 16

Which of the following is the correct formula to convert Celsius to Fahrenheit?

Accepted Answer

$$^\circ\!F = \frac{9}{5}(^\circ\!C) + 32$$

Question 17

Which of the following best describes the difference between accuracy and precision?

Accepted Answer

Accuracy is how close measurements are to the true value; precision is how close measurements are to each other.

Question 18

A sample of copper has a mass of $$374.5\ \mathrm{g}$$ and a volume of $$41.8\ \mathrm{cm^3$}. $$What is the density of copper?

Accepted Answer

$$	ext{Density} = \frac{374.5\ \mathrm{g}}{41.8\ \mathrm{cm^3$}} = 8.96\ \mathrm{g/cm^3$}$$

CHM 113 ch1

Study Guide - Practice Questions

Study Guide - Flashcards