Q: A sample of gasoline has a mass of 60.0 kg and a density of $$0.752\ \mathrm{g/cm$$^{3}$$}. $$What is the volume of the gasoline in $$\mathrm{cm$$^{3}$$}$$?

$$7.98 \times 10$$^{4}$$\ \mathrm{cm$$^{3}$$}$$

Q: Which of the following is the correct way to convert $$44.7\ \mathrm{cm} to $$inches?

$$44.7\ \mathrm{cm} \times \dfrac{1\ \mathrm{in}}{2.54\ \mathrm{cm}}$$

Question 1

NASA's Mars Climate Orbiter mission failed due to a unit conversion error. If the ground engineers entered a trajectory correction in pound·seconds instead of newton·seconds, and 1 pound·second = 4.45 newton·seconds, by what factor was the correction off?

Accepted Answer

The correction was 4.45 times too small.

Question 2

Which of the following numbers is correctly expressed in scientific notation?

Accepted Answer

$$3.2 	imes 10$$^{4}$$

Question 3

How many significant figures are in the measurement 0.00250 g?

Accepted Answer

Three

Question 4

A student measures the mass of a sample as 12.30 g and its volume as 4.5 mL. What is the density of the sample, reported to the correct number of significant figures?

Accepted Answer

$$2.7\ \mathrm{g/mL}$$

Question 5

Which of the following is the correct conversion factor to convert 56.0 cm to inches, given that $$1\ \mathrm{in} = 2.54\ \mathrm{cm}$$?

Accepted Answer

$$\dfrac{1\ \mathrm{in}}{2.54\ \mathrm{cm}}$$

Question 6

A measurement is recorded as 2.941 mL using a graduated cylinder marked every 0.1 mL. Why is this measurement incorrect?

Accepted Answer

It reports too many significant figures for the instrument's precision.

Question 7

Which of the following best describes the number of significant figures in the result of the calculation $$5.02 	imes 89.665 	imes 0.10$$?

Accepted Answer

2 significant figures

Question 8

A runner completes 10.0 km on a track that is 255 m per lap. How many laps does the runner complete, reported to the correct number of significant figures?

Accepted Answer

$$39.2\ \mathrm{laps}$$

Question 9

Which SI prefix multiplier corresponds to $$10^{-9}$$?

Accepted Answer

nano-

Question 10

A sample of gasoline has a mass of 60.0 kg and a density of $$0.752\ \mathrm{g/cm$$^{3}$$}. $$What is the volume of the gasoline in $$\mathrm{cm$$^{3}$$}$$?

Accepted Answer

$$7.98 	imes 10$$^{4}$$\ \mathrm{cm$$^{3}$$}$$

Question 11

Which of the following is the most appropriate unit to express the diameter of a polio virus, which is approximately $$2.8 	imes 10$$^{-8}$$\ \mathrm{m}$$?

Accepted Answer

nanometers (nm)

Question 12

A cylinder has a length of $$1.25\ \mathrm{cm}$$ and a diameter of $$0.50\ \mathrm{cm}. If it is $$filled with LDL (density $$1.04\ \mathrm{g/cm$$^{3}$$}$$), what is the mass of LDL in the cylinder?

Accepted Answer

$$0.255\ \mathrm{g}$$

Question 13

Which of the following statements about significant figures is TRUE?

Accepted Answer

Trailing zeros after a decimal point are always significant.

Question 14

Convert $$1255\ \mathrm{cm$$^{3}$$} to $$cubic inches using the correct conversion factor ($$1\ \mathrm{in} = 2.54\ \mathrm{cm}). $$What is the answer to four significant figures?

Accepted Answer

$$76.59\ \mathrm{in$$^{3}$$}$$

Question 15

A solution is prepared by mixing $$5.74\ \mathrm{mL}$$, $$0.823\ \mathrm{mL}$$, and $$2.651\ \mathrm{mL}. $$What is the total volume, reported to the correct number of decimal places?

Accepted Answer

$$9.21\ \mathrm{mL}$$

Question 16

Which of the following is an exact number?

Accepted Answer

1 dozen = 12

Question 17

A person has a mass of $$55.9\ \mathrm{kg}$$ and displaces $$57.2\ \mathrm{L} of $$water. What is the density of the person in $$\mathrm{g/cm$$^{3}$$}$$?

Accepted Answer

$$0.977\ \mathrm{g/cm$$^{3}$$}$$

Question 18

Which of the following is the correct way to convert $$44.7\ \mathrm{cm} to $$inches?

Accepted Answer

$$44.7\ \mathrm{cm} 	imes \dfrac{1\ \mathrm{in}}{2.54\ \mathrm{cm}}$$

Question 19

A ring has a mass of $$5.84\ \mathrm{g}$$ and a volume of $$0.556\ \mathrm{cm$$^{3}$$}. Is $$the ring made of platinum ($$21.4\ \mathrm{g/cm$$^{3}$$}$$)?

Accepted Answer

No, because its density is $$10.5\ \mathrm{g/cm$$^{3}$$}$$, which is much less than platinum.

Question 20

Which of the following best explains why units are critical in chemistry and science?

Accepted Answer

Units provide context and ensure clarity in measurements and calculations.

Measurement and Problem Solving in Chemistry: Scientific Notation, Significant Figures, Units, and Density

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