Question 1

Which of the following best describes the concept of 'significant figures' in scientific measurements?

Accepted Answer

All nonzero digits and any zeros between them or after a decimal point are significant.

Question 2

A student measures the length of a pencil as $$21.37\ \mathrm{cm}. $$Which statement is true about this measurement?

Accepted Answer

The last digit (7) is estimated, while the others are certain.

Question 3

How many significant figures are in the number $$0.02300$$?

Accepted Answer

4

Question 4

Which of the following numbers has exactly three significant figures?

Accepted Answer

$$408$$

Question 5

A laboratory thermometer reads $$98.60\ ^\circ\mathrm{F}. $$What is this temperature in Celsius? (Use $$T_\mathrm{C} = \frac{T_\mathrm{F} - 32.00}{1.800})$$

Accepted Answer

$$37.00\ ^\circ\mathrm{C}$$

Question 6

Which of the following is the correct way to report the result of $$23.451 	imes 0.042$$ using the rules for significant figures?

Accepted Answer

$$0.99$$

Question 7

When adding $$234.316 + 0.42$$, how many decimal places should the answer have?

Accepted Answer

2 decimal places, matching the least precise measurement

Question 8

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 9

Which of the following numbers is ambiguous in terms of significant figures and should be reported using scientific notation?

Accepted Answer

$$2500$$

Question 10

A student records the mass of a sample as $$0.00320\ \mathrm{g}. $$How many significant figures does this measurement have?

Accepted Answer

3

Question 11

Which of the following is the correct conversion from Celsius to Kelvin for a temperature of $$37.00\ ^\circ\mathrm{C}$$?

Accepted Answer

$$310.15\ \mathrm{K}$$

Question 12

Which of the following best explains why trailing zeros in $$2500$$ are considered ambiguous?

Accepted Answer

They only serve to locate the decimal point and may or may not be significant.

Question 13

A measurement is reported as $$1.200 	imes 10^8$. How many significant figures does it have?

Accepted Answer

4

Question 14

Which of the following is the correct rule for rounding when the leftmost digit dropped is 5 or more?

Accepted Answer

Round up.

Question 15

A chemist is performing a multi-step calculation. When should they round their answer to the correct number of significant figures?

Accepted Answer

Only at the final answer.

Question 16

Which of the following best describes the role of units in scientific measurements?

Accepted Answer

Units provide a standard of comparison and are essential for interpreting measurements.

Question 17

Which of the following is the correct number of significant figures in the measurement $$230.0$$?

Accepted Answer

4

Question 18

A student calculates the density of a liquid as $$0.8230\ \mathrm{g/mL}$$ using a mass of $$8.230\ \mathrm{g}$$ and a volume of $$10.0\ \mathrm{mL}. $$How many significant figures should the reported density have?

Accepted Answer

3

Question 19

Which of the following is a correct statement about leading zeros in a measurement?

Accepted Answer

Leading zeros are never significant.

Question 20

A real-world example: A hospital thermometer reads $$39.2\ ^\circ\mathrm{C}. $$What is this temperature in Kelvin? (Use $$T_\mathrm{K} = T_\mathrm{C} + 273.15)$$

Accepted Answer

$$312.35\ \mathrm{K}$$

Introduction to General Chemistry: Measurements, Uncertainty, and Significant Figures

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