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

$$44.7 \times \frac{1\ \text{in}}{2.54\ \text{cm}}$$

Question 1

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

Accepted Answer

$$2.5 	imes 10^1$

Question 2

A student measures the mass of a sample as 1.260 g using a scale marked every 0.1 g. Which digit is considered estimated?

Accepted Answer

The digit '0'

Question 3

How many significant figures are in the measurement 0.00450 g?

Accepted Answer

3

Question 4

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

Accepted Answer

1 in = 2.54 cm

Question 5

Convert 0.00056 to scientific notation.

Accepted Answer

$$5.6 	imes 10$$^{-4}$$

Question 6

Which rule should be followed when rounding the result of a multiplication or division calculation involving significant figures?

Accepted Answer

Round to the same number of significant figures as the input with the fewest significant figures.

Question 7

A chemist adds 5.74 g and 9.213 g. What is the correct answer, reported with the proper number of decimal places?

Accepted Answer

$$14.95$$

Question 8

Which of the following statements about trailing zeros is correct?

Accepted Answer

Trailing zeros after a decimal point are significant.

Question 9

A measurement is recorded as 100.00 m. How many significant figures does this value have?

Accepted Answer

5

Question 10

Which conversion factor would you use to convert inches to centimeters?

Accepted Answer

$$\frac{2.54\ 	ext{cm}}{1\ 	ext{in}}$$

Question 11

A student multiplies $$2.0 (2 $$sig. figs) by $$3.56 (3 $$sig. figs). What should the answer be, with the correct number of significant figures?

Accepted Answer

$$7.1$$

Question 12

Which of the following is NOT a step in converting a number to scientific notation?

Accepted Answer

Add zeros to the end of the number to increase its value.

Question 13

A student subtracts $$4.8$$ from $$3.965. $$What is the correct answer, reported with the proper number of decimal places?

Accepted Answer

$$0.8$$

Question 14

Which of the following is an example of dimensional analysis in unit conversion?

Accepted Answer

Multiplying a number by a conversion factor so that units cancel appropriately.

Question 15

How many significant figures are in the number 1.080?

Accepted Answer

4

Question 16

Which of the following is true about leading zeros?

Accepted Answer

Leading zeros are never significant; they only serve to locate the decimal point.

Question 17

A student wants to convert 44.7 cm to inches using the conversion factor $$1\ 	ext{in} = 2.54\ 	ext{cm}. $$What is the correct calculation?

Accepted Answer

$$44.7 	imes \frac{1\ 	ext{in}}{2.54\ 	ext{cm}}$$

Question 18

Which of the following statements about rounding in multi-step calculations is correct?

Accepted Answer

Round only the final answer to prevent small rounding errors from affecting the result.

Question 19

A student reports a measurement as 237.1 m. Which digits are considered certain?

Accepted Answer

2, 3, and 7

Question 20

Which of the following is the correct scientific notation for Avogadro's number, $$6,022,000,000,000,000,000,000$$?

Accepted Answer

$$6.022 	imes 10$$^{23}$$

Numbers in Chemistry: Scientific Notation, Significant Figures, and Unit Conversions

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