Question 1

A laboratory technician needs to prepare 250.0 mL of a 0.200 M NaCl solution. How many grams of NaCl (molar mass = 58.44 g/mol) are required?

Accepted Answer

$$2.92\ \mathrm{g}$$

Question 2

Which of the following numbers has exactly three significant figures?

Accepted Answer

$$3.40 	imes 10^2$

Question 3

A patient receives 500 mg of a medication every 8 hours. How many grams of the medication will the patient receive in 5 days?

Accepted Answer

$$7.5\ \mathrm{g}$$

Question 4

Which of the following is a chemical property?

Accepted Answer

Reactivity with acid

Question 5

A student measures the mass of a sample as $$12.30\ \mathrm{g}$$, $$12.32\ \mathrm{g}$$, and $$12.31\ \mathrm{g} in $$three trials. The true mass is $$12.00\ \mathrm{g}. $$Which statement best describes the measurements?

Accepted Answer

The measurements are precise but not accurate.

Question 6

Which of the following conversion factors is exact (not measured)?

Accepted Answer

$$1\ \mathrm{ft} = 12\ \mathrm{in}$$

Question 7

A solution is prepared by dissolving $$5.00\ \mathrm{g} of $$glucose ($$C_6H_{12}O_6$, molar mass = 180.16$$\ \mathrm{g/mol}$$) in enough water to make 100.0$$\ \mathrm{mL}$$ of solution. What is the molarity of the solution?

Accepted Answer

$$0.278\ \mathrm{M}$$

Question 8

Which of the following best describes a hypothesis?

Accepted Answer

A tentative explanation that can be tested by experiments.

Question 9

A sample of gas occupies $$2.50\ \mathrm{L} at$$ $$1.00\ \mathrm{atm}. If $$the pressure is increased to $$2.00\ \mathrm{atm} at $$constant temperature, what is the new volume?

Accepted Answer

$$1.25\ \mathrm{L}$$

Question 10

Which of the following is a heterogeneous mixture?

Accepted Answer

Salad dressing

Question 11

A nurse needs to administer $$0.250\ \mathrm{L} of $$saline solution. How many milliliters is this?

Accepted Answer

$$250\ \mathrm{mL}$$

Question 12

Which of the following statements about significant figures is correct?

Accepted Answer

Zeros between nonzero digits are always significant.

Question 13

A student records a temperature as $$37.0\ ^\circ\mathrm{C}. $$How many significant figures are in this measurement?

Accepted Answer

3

Question 14

Which of the following is a physical change?

Accepted Answer

Ice melting

Question 15

A solution contains $$0.500\ \mathrm{mol} of$$ $$NaCl in$$ $$250.0\ \mathrm{mL} of $$solution. What is the molarity?

Accepted Answer

$$2.00\ \mathrm{M}$$

Question 16

Which of the following is an example of a pure substance?

Accepted Answer

Distilled water

Question 17

A sample of gold has a mass of $$96.5\ \mathrm{g}$$ and a volume of $$5.00\ \mathrm{cm}^3. $$What is the density of gold?

Accepted Answer

$$19.3\ \mathrm{g/cm}^3$$

Question 18

Which of the following is the correct scientific notation for $$0.000560$$?

Accepted Answer

$$5.60 	imes 10$$^{-4}$$

Question 19

A doctor orders a dose of $$0.250\ \mathrm{g} of a $$drug. The available tablets contain $$125\ \mathrm{mg}$$ each. How many tablets should be given?

Accepted Answer

$$2$$ tablets

Question 20

Which of the following is a correct statement about the law of conservation of mass?

Accepted Answer

Mass is neither created nor destroyed in a chemical reaction.

GOB Chemistry: Measurement, Significant Figures, and Scientific Reasoning Study Guide

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