Question 1

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

Accepted Answer

The number of students in a classroom: $30$

Question 2

A laboratory scale reads $12.50$ g for a sample. How many significant figures does this measurement have?

Accepted Answer

$4$ significant figures

Question 3

Which of the following numbers has exactly $3$ significant figures?

Accepted Answer

$0.340$

Question 4

A nurse administers $10.0$ mg of a drug to a patient. Is this value exact or inexact, and why?

Accepted Answer

Inexact, because it is measured and subject to uncertainty

Question 5

How many significant figures are in the number $0.003840$?

Accepted Answer

$4$

Question 6

Which of the following statements about significant figures is correct?

Accepted Answer

Leading zeros are not significant

Question 7

A recipe calls for $12$ eggs. Is this number exact or inexact, and why?

Accepted Answer

Exact, because it is a counted value

Question 8

Which of the following measurements contains $2$ significant figures?

Accepted Answer

$2.0$

Question 9

A student records the following measurements: $0.000250$ g and $8.03 	imes 10^5$ m. How many significant figures are in each measurement, respectively?

Accepted Answer

$3$ and $3$

Question 10

Which of the following best describes an inexact number?

Accepted Answer

A value obtained from a measurement with some uncertainty

Question 11

A patient’s temperature is measured as $98.60$ °F. How many significant figures does this value have?

Accepted Answer

$4$

Question 12

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

Accepted Answer

Leading zeros are significant

Question 13

A measurement is recorded as $0.0400$ L. How many significant figures does this value have?

Accepted Answer

$3$

Question 14

Which of the following best explains why the number of students in a lecture hall is considered an exact number?

Accepted Answer

It is a value obtained by counting, with no uncertainty

Question 15

A scientist reports a result as $1.230 	imes 10^3$ mL. How many significant figures are in this value?

Accepted Answer

$4$

Question 16

Which of the following values has the greatest number of significant figures?

Accepted Answer

$4.500$

Question 17

A doctor prescribes $250$ mg of a medication. Is this value exact or inexact, and what is the reason?

Accepted Answer

Inexact, because it is measured and subject to uncertainty

Question 18

Which of the following numbers contains only $1$ significant figure?

Accepted Answer

$0.1$

Question 19

A sample is measured as $0.00560$ g. How many significant figures does this value have?

Accepted Answer

$3$

Question 20

Which of the following best describes the difference between exact and inexact numbers?

Accepted Answer

Exact numbers have no uncertainty, inexact numbers have some uncertainty

Exact vs Inexact Numbers and Significant Figures in Chemistry

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