Q: A graduated cylinder contains 53.55 mL of water. After a metal object is added, the volume rises to 67.95 mL. If the density of the metal is $$8.90\ \mathrm{g/mL}$$, what is the mass of the object?

$$m = 8.90\ \mathrm{g/mL} \times (67.95\ \mathrm{mL} - 53.55\ \mathrm{mL}) = 129\ \mathrm{g}$$

Q: Convert 3.00 gallons to milliliters. ($$1\ \mathrm{gal} = 3.7854\ \mathrm{L})$$

$$3.00\ \mathrm{gal} \times \frac{3.7854\ \mathrm{L}}{1\ \mathrm{gal}} \times \frac{1000\ \mathrm{mL}}{1\ \mathrm{L}} = 11356\ \mathrm{mL}$$

Q: Which of the following is the correct scientific notation for 0.00000045 g?

$$4.5 \times 10$$^{-7}$$\ \mathrm{g}$$

Q: A pediatric suspension contains $$100\ \mathrm{mg}/5.0\ \mathrm{mL}. $$The recommended dose is $$5.0\ \mathrm{mg}$$ per kg of body weight. How many mL of this suspension should be given to a child weighing $$18\ \mathrm{lbs}$$? ($$1\ \mathrm{kg} = 2.205\ \mathrm{lbs})$$

$$18\ \mathrm{lbs} \times \frac{1\ \mathrm{kg}}{2.205\ \mathrm{lbs}} \times \frac{5.0\ \mathrm{mg}}{1\ \mathrm{kg}} \times \frac{5.0\ \mathrm{mL}}{100\ \mathrm{mg}} = 2.0\ \mathrm{mL}$$

Q: A sample of copper displaces $$9.58\ \mathrm{mL} of $$water. If the density of copper is $$8.96\ \mathrm{g/mL}$$, what is the mass of the sample?

$$m = 8.96\ \mathrm{g/mL} \times 9.58\ \mathrm{mL} = 85.8\ \mathrm{g}$$

Question 1

Which of the following statements about significant figures is TRUE?

Accepted Answer

Captive zeros (zeros between nonzero digits) are always significant.

Question 2

A student measures the mass of a metal object as 15.62 g and its volume as 2.5 mL. What is the density of the object, reported to the correct number of significant figures?

Accepted Answer

$$d = \frac{15.62\ \mathrm{g}}{2.5\ \mathrm{mL}} = 6.2\ \mathrm{g/mL}$$

Question 3

Which of the following is an example of an exact number in chemistry?

Accepted Answer

The number of centimeters in a meter.

Question 4

A graduated cylinder contains 53.55 mL of water. After a metal object is added, the volume rises to 67.95 mL. If the density of the metal is $$8.90\ \mathrm{g/mL}$$, what is the mass of the object?

Accepted Answer

$$m = 8.90\ \mathrm{g/mL} 	imes (67.95\ \mathrm{mL} - 53.55\ \mathrm{mL}) = 129\ \mathrm{g}$$

Question 5

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

Accepted Answer

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

Question 6

Convert 3.00 gallons to milliliters. ($$1\ \mathrm{gal} = 3.7854\ \mathrm{L})$$

Accepted Answer

$$3.00\ \mathrm{gal} 	imes \frac{3.7854\ \mathrm{L}}{1\ \mathrm{gal}} 	imes \frac{1000\ \mathrm{mL}}{1\ \mathrm{L}} = 11356\ \mathrm{mL}$$

Question 7

Which of the following is the correct scientific notation for 0.00000045 g?

Accepted Answer

$$4.5 	imes 10$$^{-7}$$\ \mathrm{g}$$

Question 8

A pediatric suspension contains $$100\ \mathrm{mg}/5.0\ \mathrm{mL}. $$The recommended dose is $$5.0\ \mathrm{mg}$$ per kg of body weight. How many mL of this suspension should be given to a child weighing $$18\ \mathrm{lbs}$$? ($$1\ \mathrm{kg} = 2.205\ \mathrm{lbs})$$

Accepted Answer

$$18\ \mathrm{lbs} 	imes \frac{1\ \mathrm{kg}}{2.205\ \mathrm{lbs}} 	imes \frac{5.0\ \mathrm{mg}}{1\ \mathrm{kg}} 	imes \frac{5.0\ \mathrm{mL}}{100\ \mathrm{mg}} = 2.0\ \mathrm{mL}$$

Question 9

Which of the following is an intensive property?

Accepted Answer

Density

Question 10

A sample of copper displaces $$9.58\ \mathrm{mL} of $$water. If the density of copper is $$8.96\ \mathrm{g/mL}$$, what is the mass of the sample?

Accepted Answer

$$m = 8.96\ \mathrm{g/mL} 	imes 9.58\ \mathrm{mL} = 85.8\ \mathrm{g}$$

Question 11

Which of the following is the correct conversion factor to convert inches to centimeters?

Accepted Answer

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

Question 12

Which of the following statements about density is FALSE?

Accepted Answer

Density always increases with increasing temperature.

Question 13

A speed limit is posted as $$0.97\ \mathrm{km/min}. $$What is this speed in miles per hour? ($$1\ \mathrm{mile} = 1.609\ \mathrm{km})$$

Accepted Answer

$$0.97\ \mathrm{km/min} 	imes \frac{1\ \mathrm{mile}}{1.609\ \mathrm{km}} 	imes 60\ \mathrm{min/hr} = 36\ \mathrm{mi/hr}$$

Question 14

Which of the following is the correct way to round $$2.376 to $$three significant figures?

Accepted Answer

$$2.38$$

Question 15

Which of the following is the correct formula for density?

Accepted Answer

$$d = \frac{m}{V}$$

Question 16

Which temperature scale does NOT use a degree symbol and is based on absolute zero?

Accepted Answer

Kelvin

Question 17

A measurement is recorded as $$5.00\ \mathrm{cm}$$ using a ruler with $$0.01\ \mathrm{cm}$$ divisions. What does this indicate about the measurement?

Accepted Answer

It has three significant figures, including one estimated digit.

Question 18

Which of the following is the correct way to express $$35602 in $$scientific notation?

Accepted Answer

$$3.5602 	imes 10$$^{4}$$

Units, Measurement, Density, and Dimensional Analysis in General Chemistry

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