Q: A sample contains 3.0 moles of sodium atoms. How many atoms are present in the sample? Use Avogadro's number $$6.022 \times 10$$^{23}$$ atoms/mol.

$$1.81 \times 10$$^{24}$$ atoms

Q: Which of the following is a correct example of dimensional analysis?

Converting $$10 \text{ cm} to$$ $$0.1 \text{ m}$$ using $$1 \text{ m} = 100 \text{ cm}$$

Question 1

Which of the following best describes a chemical change?

Accepted Answer

Iron rusting when exposed to air

Question 2

Which of the following is the correct SI unit for mass?

Accepted Answer

kilogram (kg)

Question 3

A sample contains 3.0 moles of sodium atoms. How many atoms are present in the sample? Use Avogadro's number $$6.022 	imes 10$$^{23}$$ atoms/mol.

Accepted Answer

$$1.81 	imes 10$$^{24}$$ atoms

Question 4

Which of the following is an example of a homogeneous mixture?

Accepted Answer

Salt dissolved in water

Question 5

Which law states that a compound always contains the same elements in the same proportion by mass?

Accepted Answer

Law of Constant Composition

Question 6

A gold bar has a density of $$19.3 	ext{ g/cm}^3. $$What is the volume of a gold bar that weighs $$250.0 	ext{ g}$$?

Accepted Answer

$$12.95 	ext{ cm}^3$$

Question 7

Which of the following is the correct formula for ammonium sulfate?

Accepted Answer

$$(NH_4$)_2SO_4$$

Question 8

How many protons, neutrons, and electrons are present in a neutral atom of $$^{62}_{28}Ni$$?

Accepted Answer

28 protons, 34 neutrons, 28 electrons

Question 9

Which of the following is a physical property?

Accepted Answer

Density

Question 10

A patient weighing 70 kg is to receive a drug at a dosage of $$2.5 	ext{ mg/kg} of $$body weight. The drug is supplied as a solution containing $$10 	ext{ mg/mL}. $$What volume of the drug should be administered?

Accepted Answer

$$17.5 	ext{ mL}$$

Question 11

Which of the following statements about isotopes is correct?

Accepted Answer

Isotopes have the same number of protons but different numbers of neutrons.

Question 12

Which of the following compounds is an example of a polyatomic ion?

Accepted Answer

$$SO_4$$^{2-}$$

Question 13

What is the correct name for $$Fe_2O_3$$?

Accepted Answer

Iron(III) oxide

Question 14

Which of the following is the correct formula for cobalt(II) sulfate heptahydrate?

Accepted Answer

$$CoSO_4$$ \cdot 7H_2O$$

Question 15

A student mixes $$50.0 	ext{ mL} of $$water at $$20.0^\circ 	ext{C}$$ with $$50.0 	ext{ mL} of $$water at $$80.0^\circ 	ext{C}. $$What is the final temperature, assuming no heat loss?

Accepted Answer

$$50.0^\circ 	ext{C}$$

Question 16

Which of the following is a correct example of dimensional analysis?

Accepted Answer

Converting $$10 	ext{ cm} to$$ $$0.1 	ext{ m}$$ using $$1 	ext{ m} = 100 	ext{ cm}$$

Question 17

Which of the following is the correct formula for sodium dihydrogen phosphate?

Accepted Answer

$$NaH_2PO_4$$

Question 18

Which of the following best describes the physical state of matter that has a definite volume but no definite shape?

Accepted Answer

Liquid

Question 19

Which of the following is the correct name for $$H_2SO_4$$?

Accepted Answer

Sulfuric acid

Question 20

A solution contains $$5.0 	ext{ g} of $$NaCl dissolved in $$100.0 	ext{ g} of $$water. What is the mass percent of NaCl in the solution?

Accepted Answer

$$4.8\%$$

General Chemistry: Fundamental Concepts, Calculations, and Chemical Nomenclature

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