Q: Which of the following conversion factors is considered exact?

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

Question 1

Which of the following numbers is correctly written in scientific notation?

Accepted Answer

$$5.4 	imes 10$$^{1}$$

Question 2

A scientist measures the mass of a sample as 1.26 grams using a balance with markings every 0.1 gram. Which digit in this measurement is considered uncertain?

Accepted Answer

The '6' digit

Question 3

Convert the number 0.00085 to scientific notation.

Accepted Answer

$$8.5 	imes 10$$^{-5}$$

Question 4

Which of the following statements about significant figures is TRUE?

Accepted Answer

Trailing zeros after a decimal point are significant.

Question 5

A laboratory report states that the average global temperature has increased by $$0.6^{\circ}C$. What is the implied uncertainty in this measurement?

Accepted Answer

$$\pm 0.1$$^{\circ}$$C$$

Question 6

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

Accepted Answer

The number of students in a classroom

Question 7

A student records the volume of liquid in a graduated cylinder as 24.6 mL. Which digit is estimated?

Accepted Answer

6

Question 8

Which of the following measurements contains three significant figures?

Accepted Answer

0.0450

Question 9

Why is it important to read the meniscus at eye level when measuring the volume of a liquid in a graduated cylinder?

Accepted Answer

To avoid parallax error and ensure an accurate measurement

Question 10

A balance has markings every 1 gram. What is the correct way to report a mass measured between 2 and 3 grams?

Accepted Answer

2.3 grams

Question 11

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

Accepted Answer

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

Question 12

Which of the following numbers has four significant figures?

Accepted Answer

0.004560

Question 13

A student measures the diameter of a coin as 24.6 mm. Which part of this measurement is certain?

Accepted Answer

24

Question 14

Which of the following is NOT a rule for determining significant figures?

Accepted Answer

Leading zeros are significant.

Question 15

A scientist counts 12 test tubes in a rack. How many significant figures does this number have?

Accepted Answer

Unlimited

Question 16

Which of the following conversion factors is considered exact?

Accepted Answer

$$1 	ext{ in} = 2.54 	ext{ cm}$$

Question 17

A sample is measured as 0.000340 g. How many significant figures does this measurement have?

Accepted Answer

4

Question 18

Which of the following best explains why scientists use scientific notation?

Accepted Answer

To easily express very large or very small numbers

Question 19

A student records a measurement as 45.872 g. Which digit is the estimated digit?

Accepted Answer

2

Question 20

Which of the following is the correct scientific notation for the number 72900?

Accepted Answer

$$7.29 	imes 10$$^{4}$$

Measurement and Problem Solving in Chemistry: Scientific Notation, Precision, and Significant Figures

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