Q: Which of the following is the correct relationship for converting Celsius to Fahrenheit?

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

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

$$1\ \mathrm{mole} = 6.02 \times 10$$^{23}$$ units

Question 1

Which of the following statements best describes a quantitative observation in a chemistry experiment?

Accepted Answer

The temperature of the solution increased by $$5.0\ ^\circ\mathrm{C}.$$

Question 2

A student measures the mass of a sample as $$2.50\ \mathrm{g}$$ using a balance with a precision of $$\pm 0.01\ \mathrm{g}. $$Which of the following best represents the measurement and its uncertainty?

Accepted Answer

$$2.50\ \mathrm{g} \pm 0.01\ \mathrm{g}$$

Question 3

Which of the following is an example of a systematic (determinate) error in a laboratory measurement?

Accepted Answer

A balance that is not zeroed, causing all mass measurements to be 0.2 g too high.

Question 4

Convert a temperature of $$25.0\ ^\circ\mathrm{C} to $$Kelvin.

Accepted Answer

$$298.2\ \mathrm{K}$$

Question 5

Which of the following numbers has exactly three significant figures?

Accepted Answer

0.0300

Question 6

A student multiplies $$2.50\ \mathrm{cm} by$$ $$3.10\ \mathrm{cm}$$ and obtains $$7.75\ \mathrm{cm}^2. $$How should the answer be reported with the correct number of significant figures?

Accepted Answer

$$7.8\ \mathrm{cm}^2$$

Question 7

Which of the following is an intensive property?

Accepted Answer

Density

Question 8

A sample of mercury has a density of $$13.6\ \mathrm{g/cm}^3. $$What is the mass, in grams, of $$50.0\ \mathrm{mL} of $$mercury? (Assume $$1\ \mathrm{mL} = 1\ \mathrm{cm}^3)$$

Accepted Answer

$$680\ \mathrm{g}$$

Question 9

Which of the following best describes the First Law of Thermodynamics?

Accepted Answer

Energy of the universe is conserved.

Question 10

A chemical reaction in a beaker causes the temperature of the surroundings to decrease. Which of the following best describes the process?

Accepted Answer

The reaction is endothermic; heat flows from the surroundings to the system.

Question 11

Which of the following is the correct relationship for converting Celsius to Fahrenheit?

Accepted Answer

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

Question 12

A student needs to convert $$2.00\ \mathrm{ft} to $$centimeters. Which of the following conversion factors should be used?

Accepted Answer

$$1\ \mathrm{in} = 2.54\ \mathrm{cm}$$

Question 13

Which of the following is the correct scientific notation for the number 0.00450 with the correct number of significant figures?

Accepted Answer

$$4.50 	imes 10$$^{-3}$$

Question 14

A sample of gasoline has a mass of $$22\ \mathrm{mg}$$ and a density of $$0.754\ \mathrm{g/cm}^3. $$What is its volume in $$\mathrm{mL}$$? (Assume $$1\ \mathrm{cm}^3 = 1\ \mathrm{mL})$$

Accepted Answer

$$0.0292\ \mathrm{mL}$$

Question 15

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

Accepted Answer

$$1\ \mathrm{mole} = 6.02 	imes 10$$^{23}$$ units

Question 16

A student adds $$12.34\ \mathrm{g}$$, $$0.56\ \mathrm{g}$$, and $$1.2\ \mathrm{g}$$ together. What is the sum reported to the correct number of significant figures?

Accepted Answer

$$14.1\ \mathrm{g}$$

Question 17

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

Accepted Answer

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

Question 18

A $$100.0\ \mathrm{g}$$ sample of water is heated from $$25.0\ ^\circ\mathrm{C} to$$ $$75.0\ ^\circ\mathrm{C}. If $$the specific heat of water is $$4.184\ \mathrm{J/g\ ^\circ C}$$, how much energy (in joules) is absorbed?

Accepted Answer

$$20,900\ \mathrm{J}$$

Question 19

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

Accepted Answer

candela (cd)

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

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