Q: Which of the following is an exact number and therefore has an infinite number of significant figures?

$$1$$ mole $$= 6.022 \times 10$$^{23}$$ units

Question 1

Which of the following is an example of a quantitative observation?

Accepted Answer

The temperature increased by $$5.0 \, ^\circ\mathrm{C}.$$

Question 2

A student measures the mass of a sample three times and gets values of $$2.51 g$$, $$2.50 g$$, and $$2.52 g. $$The true mass is $$2.00 g. $$Which statement best describes the measurements?

Accepted Answer

The measurements are precise but not accurate.

Question 3

Which of the following numbers contains exactly three significant figures?

Accepted Answer

$$0.0300$$

Question 4

Convert $$25.0 \, ^\circ\mathrm{C} to $$Kelvin.

Accepted Answer

$$298.15 \, \mathrm{K}$$

Question 5

A graduated cylinder is marked every $$0.1 mL. If $$the meniscus is between $$4.5$$ and $$4.6 mL$$, what is the correct way to record the volume?

Accepted Answer

$$4.56 mL$$

Question 6

Which of the following is an exact number and therefore has an infinite number of significant figures?

Accepted Answer

$$1$$ mole $$= 6.022 	imes 10$$^{23}$$ units

Question 7

A sample of mercury has a density of $$13.6 g/cm$^3. $$What is the mass, in grams, of $$95.0 mL of $$mercury? (Assume $$1 mL$$ $$= 1 cm$^3)$$

Accepted Answer

$$1.29 	imes 10^3$ g

Question 8

Which of the following best describes an intensive property?

Accepted Answer

It is independent of the amount of substance present.

Question 9

A student adds $$23.46 cm $$and $$7.1 cm. $$What is the correct answer, reported to the proper number of significant figures?

Accepted Answer

$$30.6 cm$$

Question 10

Which of the following is the correct equation to convert Celsius to Fahrenheit?

Accepted Answer

$$^\circ\mathrm{F} = 1.8(^\circ\mathrm{C}) + 32$$

Question 11

A $$22 mg $$sample of gasoline has a density of $$0.754 g/cm$^3. $$What is its volume in mL?

Accepted Answer

$$0.029 mL$$

Question 12

Which of the following is a correct statement of the First Law of Thermodynamics?

Accepted Answer

Energy of the universe is conserved.

Question 13

A reaction is endothermic. Which of the following statements is true?

Accepted Answer

The energy of the system increases.

Question 14

Which of the following is the correct SI unit for luminous intensity?

Accepted Answer

candela (cd)

Question 15

A $$145$$ acre field requires $$5.50 g/m$^2 of a $$soil supplement. How many grams are needed? ($$1 km$^2 = 247$$ acres, $$1 km$^2 = 10^6$ m^2$)

Accepted Answer

$$3.23 	imes 10^5$ g

Question 16

Which of the following is the correct relationship for kinetic energy?

Accepted Answer

$$KE = \frac{1}{2}mv^2$

Question 17

Which of the following is NOT a base SI unit?

Accepted Answer

liter (L)

Question 18

A student multiplies $$6.0 cm by$$ $$4.00 cm. $$What is the answer, reported to the correct number of significant figures?

Accepted Answer

$$24 cm$^2$$

Question 19

Which of the following is a correct conversion factor for $$1$$ inch $$= 2.54 cm$$?

Accepted Answer

$$\frac{2.54\,\mathrm{cm}}{1\,\mathrm{in}}$$

Question 20

Which of the following best describes a systematic (determinate) error?

Accepted Answer

It is always in the same direction.

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

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