Q: A scientist measures the length of an object as $$120.65 cm $$and the width as $$4.2 cm. $$What is the area, reported with the correct number of significant figures?

$$120.65 \times 4.2 = 507 cm$^2$$

Question 1

Which of the following 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 penny five times and gets the following results: 2.75 g, 2.76 g, 2.74 g, 2.75 g, and 2.76 g. The accepted mass of a penny is 2.50 g. Which statement best describes the student's measurements?

Accepted Answer

The measurements are precise but not accurate.

Question 3

How many significant figures are in the number 0.005920?

Accepted Answer

4

Question 4

Which of the following numbers has exactly three significant figures?

Accepted Answer

0.00960

Question 5

A student records a measurement as 96,500 g. How many significant figures does this number have?

Accepted Answer

3

Question 6

When adding 58.15 mL and 90.0 mL, what is the correct way to report the sum based on significant figures?

Accepted Answer

$$58.15 + 90.0 = 148.2 mL$ (rounded to the tenths place)$$

Question 7

You are asked to multiply $$2.683$$ meters by $$5.13. $$How many significant figures should your answer have?

Accepted Answer

3

Question 8

Which of the following statements about zeros is correct according to the rules of significant figures?

Accepted Answer

Zeros between nonzero digits are always significant.

Question 9

A scientist measures the length of an object as $$120.65 cm $$and the width as $$4.2 cm. $$What is the area, reported with the correct number of significant figures?

Accepted Answer

$$120.65 	imes 4.2 = 507 cm$^2$$

Question 10

If you subtract $$13.36 g $$from $$6.5371 g$$, how many decimal places should your answer have?

Accepted Answer

Two decimal places

Question 11

Which of the following best explains why the number of significant figures in a calculated answer is important in scientific reporting?

Accepted Answer

It reflects the certainty and precision of the measurements used in the calculation.

Question 12

A student multiplies $$2.50$$ grams by $$13.8 mL $$and gets $$34.5 g/mL. $$How many significant figures should the answer have?

Accepted Answer

2

Question 13

Which of the following is the correct way to round the result of $$2.683 	imes 5.13 to $$the appropriate number of significant figures?

Accepted Answer

$$13.8$$

Question 14

Why is it incorrect to report a calculated answer with more significant figures than the least precise measurement used in the calculation?

Accepted Answer

It implies a false level of certainty in the result.

Question 15

In a multi-step calculation involving both addition and multiplication, which rule should you follow for reporting the final answer's significant figures?

Accepted Answer

Apply the rule for each operation and use the least number of significant figures or decimal places as appropriate for the final answer.

Question 16

A measurement is recorded as $$0.00450 kg. $$How many significant figures does this value have?

Accepted Answer

3

Question 17

Which of the following best describes the effect of using a calculator that displays more digits than are significant in your measurements?

Accepted Answer

You must round your answer to the correct number of significant figures to reflect the certainty of your measurements.

Question 18

Which of the following is a correct statement about trailing zeros in significant figures?

Accepted Answer

Trailing zeros are only significant if there is a decimal point present.

Question 19

A student measures the volume of a liquid as $$58.15 mL $$and then adds an object, raising the volume to $$90.0 mL. $$What is the volume of the object, reported with the correct number of decimal places?

Accepted Answer

$$31.9 mL$$

Question 20

Which of the following best explains why significant figures are important in scientific communication?

Accepted Answer

They communicate the precision and reliability of the measurements to others.

Significant Figures: Concepts, Rules, and Applications in Scientific Measurement

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