Question 1

Which of the following is the correct SI base unit for measuring the amount of substance?

Accepted Answer

Mole (mol)

Question 2

A laboratory measurement is reported as $$23.46 \pm 0.04 mg. $$What does the $$\pm 0.04 mg $$represent?

Accepted Answer

The uncertainty in the last digit of the measurement

Question 3

Which of the following numbers has exactly three significant figures?

Accepted Answer

$$536$$

Question 4

Convert $$3.4 	imes 10$$^{-6}$$ meters to a unit using a metric prefix.

Accepted Answer

$$3.4$$ micrometers

Question 5

A hunk of alligator tail weighs $$0.432 kg. $$What is this mass in ounces? (Given: $$1 kg$$ $$= 2.2046 lb$$, $$1 lb$$ $$= 16 oz)$$

Accepted Answer

$$6.93 oz$$

Question 6

Which of the following is an exact number and does NOT affect the number of significant figures in a calculation?

Accepted Answer

$$1$$ inch $$= 2.54 cm$$

Question 7

A grain of pollen has a mass of $$8 ng. $$Express this mass in kilograms using scientific notation.

Accepted Answer

$$8 	imes 10$$^{-12}$$ kg

Question 8

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

Accepted Answer

Precision is how close measurements are to each other; accuracy is how close measurements are to the true value.

Question 9

What is the correct answer, with the proper number of significant figures, for the following calculation: $$\frac{2.6596}{12.01 + 14.007}$$?

Accepted Answer

$$0.104$$

Question 10

A $$10-cm $$cube contains $$1000$$ $$1-cm $$cubes. What is the volume of the $$10-cm $$cube in $$cm^3$$?

Accepted Answer

$$1000$$ 	ext{ cm}^3$

Question 11

The speed of light in a vacuum is $$3.00 	imes 10^8$ m/s. What is this speed in miles per hour? (Given: 1$ mile = 1.609$ km, 1$ km = 1000$ m, 1$ hour = 3600$ s)

Accepted Answer

$$6.71 	imes 10^5$ mph

Question 12

Which of the following is the correct prefix and symbol for $$10^{-12}$$?

Accepted Answer

pico (p)

Question 13

Which of the following measurements is expressed with the correct number of significant figures after performing the operation: $$2.1 	imes 4.005 	imes 4.5654$$?

Accepted Answer

$$38.4$$

Question 14

A human chromosome contains about $$6.25 	imes 10^9$ DNA base pairs. If each base pair has a mass of 1.10$$ 	imes $$10^{-21} g$$, what is the total mass in grams?

Accepted Answer

$$6.88 	imes 10$$^{-12}$$ g

Question 15

Which of the following is a derived SI unit?

Accepted Answer

Liter (L)

Question 16

Which of the following is the best unit to express a mass of $$100,000,000,000 kg$$?

Accepted Answer

100 Tg

Question 17

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

Accepted Answer

Zeroes to the right of a nonzero digit in a whole number are always significant.

Question 18

Which of the following conversions is exact and should not limit the number of significant figures in a calculation?

Accepted Answer

$$1$$ inch $$= 2.54 cm$$

Question 19

Which of the following best describes the measurement shown in the third target (image 3) in the precision vs. accuracy diagram?

Accepted Answer

Low accuracy, low precision

Essentials of Units, Measurement, and Problem Solving in General Chemistry

Guida di studio - Domande di pratica

Study guide - Flashcard