Q: A recipe makes 18 servings and requires 0.50 pounds of chocolate truffle. If you want to make 54 servings, how many pounds of chocolate truffle are needed? Use appropriate conversion factors.

$$0.50 \text{ lb} \times \frac{54 \text{ servings}}{18 \text{ servings}} = 1.5 \text{ lb}$$

Q: Which of the following is a correct conversion factor for converting hours to seconds?

$$1 \text{ hr} = 3600 \text{ s}$$

Q: A patient has approximately 83 mL of blood pumped by their heart at each beat. If their pulse is 75 beats per minute, how much blood is pumped in one day? (Use $$1 \text{ L} = 1000 \text{ mL})$$

$$83 \text{ mL/beat} \times 75 \text{ beats/min} \times 60 \text{ min/hr} \times 24 \text{ hr/day} = 8.964 \times 10^5$ \text{ mL}$$

Q: Which of the following is NOT a common conversion factor for length, mass, or volume?

$$1 \text{ g} = 1000 \text{ kg}$$

Q: While packing for a trip to Spain, a traveler wishes to weigh their luggage in kilograms to make sure it doesn’t exceed 23 kilograms. If their luggage weighs 50 pounds, which conversion factor should they use?

$$1 \text{ kg} = 2.205 \text{ lb}$$

Q: For 7 hours, an intravenous bag delivers medication to a patient at a rate of 2.75 drops per second with a mass of 42 mg per drop. What is the total mass of medication delivered? (Use $$1 \text{ hr} = 3600 \text{ s})$$

$$2.75 \text{ drops/s} \times 3600 \text{ s/hr} \times 7 \text{ hr} \times 42 \text{ mg/drop} = 2,907,000 \text{ mg}$$

Q: A prescription drug has a recommended dosage of 1 mg/kg. A 75 kg adult receives three tablets, each weighing 125 mg. Did the patient receive the correct dosage?

No, because $$3 \times 125 \text{ mg} = 375 \text{ mg}$$, which is much higher than the recommended $$75 \text{ mg}.$$

Q: If a car travels at a speed of 60 miles per hour, how many meters does it travel in 2 hours? (Use $$1 \text{ mile} = 1609 \text{ m})$$

$$60 \text{ mi/hr} \times 2 \text{ hr} \times 1609 \text{ m/mi} = 193,080 \text{ m}$$

Question 1

Which of the following best defines a conversion factor?

Accepted Answer

A ratio or fraction that has two quantities with different units.

Question 2

A recipe makes 18 servings and requires 0.50 pounds of chocolate truffle. If you want to make 54 servings, how many pounds of chocolate truffle are needed? Use appropriate conversion factors.

Accepted Answer

$$0.50 	ext{ lb} 	imes \frac{54 	ext{ servings}}{18 	ext{ servings}} = 1.5 	ext{ lb}$$

Question 3

Which of the following is a correct conversion factor for converting hours to seconds?

Accepted Answer

$$1 	ext{ hr} = 3600 	ext{ s}$$

Question 4

A patient has approximately 83 mL of blood pumped by their heart at each beat. If their pulse is 75 beats per minute, how much blood is pumped in one day? (Use $$1 	ext{ L} = 1000 	ext{ mL})$$

Accepted Answer

$$83 	ext{ mL/beat} 	imes 75 	ext{ beats/min} 	imes 60 	ext{ min/hr} 	imes 24 	ext{ hr/day} = 8.964 	imes 10^5$ 	ext{ mL}$$

Question 5

Which of the following is NOT a common conversion factor for length, mass, or volume?

Accepted Answer

$$1 	ext{ g} = 1000 	ext{ kg}$$

Question 6

While packing for a trip to Spain, a traveler wishes to weigh their luggage in kilograms to make sure it doesn’t exceed 23 kilograms. If their luggage weighs 50 pounds, which conversion factor should they use?

Accepted Answer

$$1 	ext{ kg} = 2.205 	ext{ lb}$$

Question 7

For 7 hours, an intravenous bag delivers medication to a patient at a rate of 2.75 drops per second with a mass of 42 mg per drop. What is the total mass of medication delivered? (Use $$1 	ext{ hr} = 3600 	ext{ s})$$

Accepted Answer

$$2.75 	ext{ drops/s} 	imes 3600 	ext{ s/hr} 	imes 7 	ext{ hr} 	imes 42 	ext{ mg/drop} = 2,907,000 	ext{ mg}$$

Question 8

A prescription drug has a recommended dosage of 1 mg/kg. A 75 kg adult receives three tablets, each weighing 125 mg. Did the patient receive the correct dosage?

Accepted Answer

No, because $$3 	imes 125 	ext{ mg} = 375 	ext{ mg}$$, which is much higher than the recommended $$75 	ext{ mg}.$$

Question 9

Which of the following best describes the process of dimensional analysis?

Accepted Answer

A method for converting between units using conversion factors.

Question 10

If a car travels at a speed of 60 miles per hour, how many meters does it travel in 2 hours? (Use $$1 	ext{ mile} = 1609 	ext{ m})$$

Accepted Answer

$$60 	ext{ mi/hr} 	imes 2 	ext{ hr} 	imes 1609 	ext{ m/mi} = 193,080 	ext{ m}$$

Question 11

Which of the following is the correct sequence of conversion factors to convert 5 days into seconds?

Accepted Answer

$$5 	ext{ days} 	imes \frac{24 	ext{ hr}}{1 	ext{ day}} 	imes \frac{60 	ext{ min}}{1 	ext{ hr}} 	imes \frac{60 	ext{ s}}{1 	ext{ min}}$$

Measurement and Problem Solving: Conversion Factors in Chemistry

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