Q: Convert 2.50 hours to seconds using dimensional analysis.

$$2.50 \times 60 \times 60 = 9000$$ seconds

Q: Which of the following is a correct conversion factor for changing meters to centimeters?

$$\frac{100 \text{ cm}}{1 \text{ m}}$$

Q: A chemist has 24.0 g of a substance with a density of 2.0 g/mL. What is the volume in mL?

$$24.0 \text{ g} \div 2.0 \text{ g/mL} = 12 \text{ mL}$$

Q: A student converts 60.0 miles per hour to kilometers per hour using the conversion factor $$1 \text{ mi} = 1.609 \text{ km}. $$What is the correct answer with proper significant figures?

$$60.0 \text{ mi/h} \times 1.609 = 96.5 \text{ km/h}$$

Question 1

Which of the following statements best describes the difference between accuracy and precision in scientific measurements?

Accepted Answer

Accuracy refers to how close measurements are to the true value, while precision refers to how close measurements are to each other.

Question 2

A student measures the mass of a sample three times and records 12.1 g, 12.2 g, and 12.1 g. The true mass is 15.0 g. Which statement is correct?

Accepted Answer

The measurements are precise but not accurate.

Question 3

Which of the following is a derived SI unit?

Accepted Answer

joule (J)

Question 4

How many significant figures are in the measurement 0.00450 g?

Accepted Answer

3

Question 5

Which metric prefix represents $$10^{-6}$$?

Accepted Answer

micro-

Question 6

A measurement is reported as 2500 mL. Why is this value considered ambiguous in terms of significant figures?

Accepted Answer

It is not written in scientific notation, so the number of significant figures is unclear.

Question 7

Which of the following is the correct way to report the sum of 12.11 and 3.2, considering significant figures?

Accepted Answer

$$12.11 + 3.2 = 15.3$$

Question 8

Convert 2.50 hours to seconds using dimensional analysis.

Accepted Answer

$$2.50 	imes 60 	imes 60 = 9000$$ seconds

Question 9

Which of the following is a correct conversion factor for changing meters to centimeters?

Accepted Answer

$$\frac{100 	ext{ cm}}{1 	ext{ m}}$$

Question 10

A chemist has 24.0 g of a substance with a density of 2.0 g/mL. What is the volume in mL?

Accepted Answer

$$24.0 	ext{ g} \div 2.0 	ext{ g/mL} = 12 	ext{ mL}$$

Question 11

Which of the following best explains why units are essential in scientific measurements?

Accepted Answer

Units provide meaning to the numerical value, allowing for proper interpretation and comparison.

Question 12

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

Accepted Answer

The number of students in a classroom.

Question 13

A student converts 60.0 miles per hour to kilometers per hour using the conversion factor $$1 	ext{ mi} = 1.609 	ext{ km}. $$What is the correct answer with proper significant figures?

Accepted Answer

$$60.0 	ext{ mi/h} 	imes 1.609 = 96.5 	ext{ km/h}$$

Question 14

Which of the following best describes a conversion factor?

Accepted Answer

A ratio equal to 1 that changes the unit without changing the quantity.

Question 15

If a ruler is marked in millimeters, how should you report a measurement taken with it?

Accepted Answer

To the nearest millimeter, estimating one more place.

Question 16

Which of the following is the correct way to express 0.000123 m in scientific notation with the correct number of significant figures?

Accepted Answer

$$1.23 	imes 10$$^{-4}$$ m

Question 17

A student multiplies $$3.24 by$$ $$1.7. $$How many significant figures should the answer have?

Accepted Answer

2

Question 18

Which of the following is a correct statement about switching between mass and volume?

Accepted Answer

You need to use a physical relationship such as density.

Question 19

Why did Andrew Waugh report the height of Mount Everest as 29,002 feet instead of 29,000 feet?

Accepted Answer

He was concerned people would think 29,000 feet was rounded, not measured.

Question 20

Which of the following best summarizes the purpose of dimensional analysis in chemistry?

Accepted Answer

To convert between units and ensure the final answer has the correct units.

Significant Figures and Dimensional Analysis: Measurement in Chemistry

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