Q: Convert 2.5 meters to millimeters using the correct conversion factor.

$$2.5\ \mathrm{m} \times \frac{1000\ \mathrm{mm}}{1\ \mathrm{m}} = 2500\ \mathrm{mm}$$

Q: A pharmacist needs to prepare 4.00 ounces of ointment. If 1 lb = 16 oz and 1 lb = 454 g, how many grams of ointment are needed?

$$4.00\ \mathrm{oz} \times \frac{1\ \mathrm{lb}}{16\ \mathrm{oz}} \times \frac{454\ \mathrm{g}}{1\ \mathrm{lb}} = 114\ \mathrm{g}$$

Q: A recipe calls for 18 drops of vanilla. If 1 dash = 3 drops, how many dashes are needed?

$$18\ \mathrm{drops} \times \frac{1\ \mathrm{dash}}{3\ \mathrm{drops}} = 6\ \mathrm{dashes}$$

Q: A student walks 7.5 km at a pace of 65 m/min. How many minutes does it take to complete the walk?

$$7.5\ \mathrm{km} \times \frac{1000\ \mathrm{m}}{1\ \mathrm{km}} \times \frac{1\ \mathrm{min}}{65\ \mathrm{m}} \approx 115\ \mathrm{min}$$

Q: Which of the following is the correct formula for density?

$$d = \frac{\text{mass}}{\text{volume}}$$

Question 1

Which of the following best describes the difference between mass and weight in the context of chemistry?

Accepted Answer

Mass is the amount of matter in an object, while weight is the force exerted by gravity on that mass.

Question 2

A sample of medication has a mass of 3.85 g and a volume of 3.00 mL. What is its density in $$\mathrm{g/mL}$$?

Accepted Answer

$$1.28\ \mathrm{g/mL}$$

Question 3

Which of the following numbers has the correct number of significant figures for the measurement 0.00340 g?

Accepted Answer

Three significant figures

Question 4

Convert 2.5 meters to millimeters using the correct conversion factor.

Accepted Answer

$$2.5\ \mathrm{m} 	imes \frac{1000\ \mathrm{mm}}{1\ \mathrm{m}} = 2500\ \mathrm{mm}$$

Question 5

A student records the following measurements: 4.55 cm, 3.0 cm, and 4.5 cm. Which statement about significant figures is correct?

Accepted Answer

4.55 cm has three significant figures, 3.0 cm has two, and 4.5 cm has two.

Question 6

A graduated cylinder contains 35.0 mL of water. After a copper nugget is added, the volume rises to 46.0 mL. If the nugget has a mass of 98.1 g, what is the density of copper?

Accepted Answer

$$\frac{98.1\ \mathrm{g}}{11.0\ \mathrm{mL}} = 8.92\ \mathrm{g/mL}$$

Question 7

Which of the following is the correct scientific notation for 0.00086?

Accepted Answer

$$8.6 	imes 10$$^{-4}$$

Question 8

A pharmacist needs to prepare 4.00 ounces of ointment. If 1 lb = 16 oz and 1 lb = 454 g, how many grams of ointment are needed?

Accepted Answer

$$4.00\ \mathrm{oz} 	imes \frac{1\ \mathrm{lb}}{16\ \mathrm{oz}} 	imes \frac{454\ \mathrm{g}}{1\ \mathrm{lb}} = 114\ \mathrm{g}$$

Question 9

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

Accepted Answer

1 L = 1000 mL

Question 10

A recipe calls for 18 drops of vanilla. If 1 dash = 3 drops, how many dashes are needed?

Accepted Answer

$$18\ \mathrm{drops} 	imes \frac{1\ \mathrm{dash}}{3\ \mathrm{drops}} = 6\ \mathrm{dashes}$$

Question 11

Which of the following is the correct equality for converting between liters and milliliters?

Accepted Answer

$$1\ \mathrm{L} = 1000\ \mathrm{mL}$$

Question 12

A 13.5 mL sample of an unknown liquid has a mass of 12.4 g. What is the density of the liquid?

Accepted Answer

$$\frac{12.4\ \mathrm{g}}{13.5\ \mathrm{mL}} = 0.919\ \mathrm{g/mL}$$

Question 13

Which of the following is the correct way to round 56.982 g to two significant figures?

Accepted Answer

57 g

Question 14

A student walks 7.5 km at a pace of 65 m/min. How many minutes does it take to complete the walk?

Accepted Answer

$$7.5\ \mathrm{km} 	imes \frac{1000\ \mathrm{m}}{1\ \mathrm{km}} 	imes \frac{1\ \mathrm{min}}{65\ \mathrm{m}} \approx 115\ \mathrm{min}$$

Question 15

Which of the following is the correct formula for density?

Accepted Answer

$$d = \frac{	ext{mass}}{	ext{volume}}$$

Question 16

The density of ether is $$0.714\ \mathrm{g/mL}. $$What is the mass of $$25.0\ \mathrm{mL} of $$ether?

Accepted Answer

$$0.714\ \mathrm{g/mL} 	imes 25.0\ \mathrm{mL} = 17.85\ \mathrm{g}$$

Introductory Chemistry: Measurement, Scientific Notation, and Problem Solving

Guida di studio - Domande di pratica

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