$$12.0\ \mathrm{g} \times \frac{1\ \mathrm{mol}}{18.0\ \mathrm{g}}$$

It is $$6.02 \times 10$$^{23}$$ particles in 1 mole.

Question 1

Which of the following correctly expresses 0.00056 in scientific notation?

Accepted Answer

$$5.6 	imes 10$$^{-4}$$

Question 2

A student measures the mass of a liquid as 45.2 g and its volume as 12.0 mL. What is the density of the liquid?

Accepted Answer

$$3.77\ \mathrm{g/mL}$$

Question 3

Which metric prefix represents $$10^{-3}$$?

Accepted Answer

milli-

Question 4

A block of metal has a mass of 250 g and a volume of 50.0 cm$$^3. $$Will it float in water? (Density of water = $$1.00\ \mathrm{g/cm^3$})$$

Accepted Answer

No, because its density is greater than water.

Question 5

Which of the following is a physical change?

Accepted Answer

Melting ice

Question 6

How many significant figures are in the measurement 0.00450?

Accepted Answer

3

Question 7

Which of the following is a mixture?

Accepted Answer

Air

Question 8

A sample contains $$3.01 	imes 10$$^{23}$$ molecules of CO_2$. How many moles of CO_2$ are present?

Accepted Answer

$$0.50$$ mol

Question 9

Which equation is used to calculate the mass of a substance if its density and volume are known?

Accepted Answer

$$M = D 	imes V$$

Question 10

A student needs to convert 5.0 km to meters. Which conversion factor should be used?

Accepted Answer

$$1\ \mathrm{km} = 1000\ \mathrm{m}$$

Question 11

Which of the following best describes a chemical property?

Accepted Answer

Ability to react with acid

Question 12

A student wants to convert 12.0 g of H$$_2O to $$moles. What is the correct setup using the molar mass of water ($$18.0\ \mathrm{g/mol}$$)?

Accepted Answer

$$12.0\ \mathrm{g} 	imes \frac{1\ \mathrm{mol}}{18.0\ \mathrm{g}}$$

Question 13

Which of the following is NOT a correct use of significant figures?

Accepted Answer

Reporting 0.050 as 0.05 (2 sig figs)

Question 14

Which of the following is a pure substance?

Accepted Answer

Carbon dioxide (CO$$_2)$$

Question 15

A sample of ethanol has a density of $$0.789\ \mathrm{g/mL}. $$What is the mass of 25.0 mL of ethanol?

Accepted Answer

$$19.7\ \mathrm{g}$$

Question 16

Which of the following statements about Avogadro's number is correct?

Accepted Answer

It is $$6.02 	imes 10$$^{23}$$ particles in 1 mole.

Question 17

Which of the following is the correct scientific notation for 123,000?

Accepted Answer

$$1.23 	imes 10$$^{5}$$

Question 18

A student mixes sand and salt. Which classification best describes the result?

Accepted Answer

Mixture

Question 19

Which of the following is the correct formula to find volume if mass and density are known?

Accepted Answer

$$V = \frac{M}{D}$$

Question 20

A student has 0.75 moles of NaCl. How many formula units of NaCl does this represent? (Avogadro's number = $$6.02 	imes 10$$^{23}$$)

Accepted Answer

$$4.52 	imes 10$$^{23}$$

Introduction to Chemistry: Measurement, Density, Matter, and Moles

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