Q: Which of the following conversion factors would you use to convert meters to kilometers?

$$\frac{1 \text{ km}}{1000 \text{ m}}$$

Q: A solution contains $$32 mg/mL of a $$drug. What is this concentration in g/L?

$$32 mg/mL$$ \times \frac{1 \text{ g}}{1000 \text{ mg}} \times 1000 \text{ mL}/1 \text{ L} = 32$ g/L

Q: When converting $$5.0 in$^2 to cm$^2$$, which conversion factor should be used?

$$\left(\frac{2.54 \text{ cm}}{1 \text{ in}}\$$right)^2$$

Question 1

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

Accepted Answer

$$5.2 	imes 10^3$

Question 2

A laboratory balance shows a mass reading of 12.30 g. Which statement best describes the certainty of this measurement?

Accepted Answer

The last digit (0) is estimated and indicates uncertainty.

Question 3

Express the number 0.000456 in scientific notation.

Accepted Answer

$$4.56 	imes 10$$^{-4}$$

Question 4

How many significant figures are in the measurement 0.00450 m?

Accepted Answer

3

Question 5

Which of the following is an exact number?

Accepted Answer

The number of students in a classroom

Question 6

A student multiplies $$2.34 (3 $$sig figs) by $$0.056 (2 $$sig figs) and gets $$0.13104. $$According to the rules for significant figures, what should the answer be reported as?

Accepted Answer

$$0.13$$

Question 7

Which of the following correctly describes the difference between mass and weight?

Accepted Answer

Mass is a measure of matter, weight is a measure of gravitational pull.

Question 8

Convert $$5.67 	imes 10^3$ mg to grams using scientific notation.

Accepted Answer

$$5.67 g$$

Question 9

A car is traveling at $$90 km/hr. $$What is its speed in m/s? ($$1 km$$ = $$1000 m$$, $$1 hr$$ = $$3600 s)$$

Accepted Answer

$$25 m/s$$

Question 10

Which SI base units correspond to length, mass, and time, respectively?

Accepted Answer

meter, kilogram, second

Question 11

A sample of an unknown metal has a mass of $$31.5 g $$and a volume of $$3.11 cm$^3. $$What is its density?

Accepted Answer

$$10.1 g/cm$^3$$

Question 12

Which of the following conversion factors would you use to convert meters to kilometers?

Accepted Answer

$$\frac{1 	ext{ km}}{1000 	ext{ m}}$$

Question 13

A classroom has a volume of $$285 m$^3. $$What is this volume in cm$$^3$$? ($$1 m$$ = $$100 cm$)$$

Accepted Answer

$$2.85 	imes 10^8$ cm^3$

Question 14

A solution contains $$32 mg/mL of a $$drug. What is this concentration in g/L?

Accepted Answer

$$32 mg/mL$$ 	imes \frac{1 	ext{ g}}{1000 	ext{ mg}} 	imes 1000 	ext{ mL}/1 	ext{ L} = 32$ g/L

Question 15

A drop of acetone has a mass of $$35 mg $$and a density of $$0.788 g/cm$^3. $$What is its volume in cm$$^3$$?

Accepted Answer

$$0.044 cm$^3$$

Question 16

When converting $$5.0 in$^2 to cm$^2$$, which conversion factor should be used?

Accepted Answer

$$\left(\frac{2.54 	ext{ cm}}{1 	ext{ in}}\$$right)^2$$

Question 17

A calculation involves the following steps: $$(4.56 + 1.2) 	imes 3.45. $$According to significant figure rules, how many significant figures should the final answer have?

Accepted Answer

2

Question 18

Which of the following is the most appropriate SI prefix to express the length of a typical chemical bond ($$1.2 	imes 10$$^{-10}$$ m)?

Accepted Answer

pico-

Question 19

A metal cylinder has a volume of $$246 cm$^3$$ and a density of $$7.93 g/cm$^3. $$What is its mass in grams?

Accepted Answer

$$1950 g$$

Measurement and Problem Solving in Chemistry: Scientific Notation and Uncertainty

Guida di studio - Domande di pratica

Study guide - Flashcard