Q: Which of the following is the correct sequence of unit conversions to determine the average speed in miles per hour for a runner who travels a distance in feet over a time in minutes?

$$\text{ft} \rightarrow \text{mi}$$, $$\text{min} \rightarrow \text{hr}$$

Q: A student needs to convert $$2500 \text{ ft} to $$kilometers. Which conversion factors should be used in sequence?

$$\text{ft} \rightarrow \text{m} \rightarrow \text{km}$$

Q: Which of the following is the correct formula for converting a speed from feet per minute to miles per hour?

$$\text{mi/hr} = \frac{\text{ft/min} \times 60}{5280}$$

Question 1

A runner covers 4043 ft in 7.25 minutes. What is the runner's average speed in miles per hour? (Use $$1 	ext{ mile} = 5280 	ext{ ft})$$

Accepted Answer

$$6.337 	ext{ mi/hr}$$

Question 2

Which of the following is the correct sequence of unit conversions to determine the average speed in miles per hour for a runner who travels a distance in feet over a time in minutes?

Accepted Answer

$$	ext{ft} ightarrow 	ext{mi}$$, $$	ext{min} ightarrow 	ext{hr}$$

Question 3

If a cyclist travels 10,560 ft in 15 minutes, what is their average speed in miles per hour? ($$1 	ext{ mile} = 5280 	ext{ ft})$$

Accepted Answer

$$8.0 	ext{ mi/hr}$$

Question 4

A car travels at a speed of $$60 	ext{ mi/hr}. $$What is this speed in feet per second? ($$1 	ext{ mile} = 5280 	ext{ ft}$$, $$1 	ext{ hr} = 3600 	ext{ s})$$

Accepted Answer

$$88 	ext{ ft/s}$$

Question 5

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

Accepted Answer

A method for converting units by multiplying by conversion factors so that unwanted units cancel and desired units remain.

Question 6

A student needs to convert $$2500 	ext{ ft} to $$kilometers. Which conversion factors should be used in sequence?

Accepted Answer

$$	ext{ft} ightarrow 	ext{m} ightarrow 	ext{km}$$

Question 7

A marathon is $$26.2$$ miles long. How many feet is this? ($$1 	ext{ mile} = 5280 	ext{ ft})$$

Accepted Answer

$$138,336 	ext{ ft}$$

Question 8

A chemical reaction requires $$2.5$$ hours to complete. How many seconds is this? ($$1 	ext{ hr} = 3600 	ext{ s})$$

Accepted Answer

$$9000 	ext{ s}$$

Question 9

A patient receives a dose of medication at $$0.5 	ext{ mg/kg}$$ body weight. If the patient weighs $$154 	ext{ lb}$$, how many milligrams of medication should be administered? ($$1 	ext{ kg} = 2.2046 	ext{ lb})$$

Accepted Answer

$$35 	ext{ mg}$$

Question 10

Which of the following is a common mistake when performing unit conversions in chemistry?

Accepted Answer

Failing to cancel units properly, resulting in incorrect final units.

Question 11

A laboratory experiment requires $$250 	ext{ mL} of $$solution. How many liters is this? ($$1 	ext{ L} = 1000 	ext{ mL})$$

Accepted Answer

$$0.25 	ext{ L}$$

Question 12

A car travels $$120 	ext{ km} in$$ $$2$$ hours. What is its average speed in meters per second? ($$1 	ext{ km} = 1000 	ext{ m}$$, $$1 	ext{ hr} = 3600 	ext{ s})$$

Accepted Answer

$$16.67 	ext{ m/s}$$

Question 13

Which of the following best explains why unit conversion is essential in scientific communication?

Accepted Answer

It ensures that measurements are understood and comparable across different systems and regions.

Question 14

A recipe calls for $$2.5$$ cups of water. How many milliliters is this? ($$1 	ext{ cup} = 237 	ext{ mL})$$

Accepted Answer

$$592.5 	ext{ mL}$$

Question 15

A student measures a distance as $$3.2 	ext{ km}. $$How many feet is this? ($$1 	ext{ km} = 1000 	ext{ m}$$, $$1 	ext{ m} = 3.281 	ext{ ft})$$

Accepted Answer

$$10,499.2 	ext{ ft}$$

Question 16

A chemical solution contains $$0.75 	ext{ L} of $$water. How many milliliters is this? ($$1 	ext{ L} = 1000 	ext{ mL})$$

Accepted Answer

$$750 	ext{ mL}$$

Question 17

A runner completes a $$5 	ext{ km}$$ race in $$25$$ minutes. What is their average speed in miles per hour? ($$1 	ext{ km} = 0.6214 	ext{ mi})$$

Accepted Answer

$$7.46 	ext{ mi/hr}$$

Question 18

Which of the following is the correct formula for converting a speed from feet per minute to miles per hour?

Accepted Answer

$$	ext{mi/hr} = \frac{	ext{ft/min} 	imes 60}{5280}$$

Question 19

A scientist needs to prepare $$500 	ext{ mL} of a $$solution. How many liters is this? ($$1 	ext{ L} = 1000 	ext{ mL})$$

Accepted Answer

$$0.5 	ext{ L}$$

Unit Conversion and Average Speed Calculations in Chemistry

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