Q: How many molecules are present in 2.5 moles of H$$_2O$$? Use Avogadro's number in your calculation.

$$2.5 \times 6.022 \times 10$$^{23}$$ = 1.51 \times 10$$^{24}$$ molecules

Q: What is the mass in grams of 0.75 moles of NH$$_3$$? (Molar mass of NH$$_3 = 17.03 g/$$mol)

$$0.75 \times 17.03 = 12.77 g$$

Question 1

How many molecules are present in 2.5 moles of H$$_2O$$? Use Avogadro's number in your calculation.

Accepted Answer

$$2.5 	imes 6.022 	imes 10$$^{23}$$ = 1.51 	imes 10$$^{24}$$ molecules

Question 2

Which of the following statements about ionic and molecular formulas is correct?

Accepted Answer

Ionic formulas show the smallest whole number ratio of ions.

Question 3

What is the mass in grams of 0.75 moles of NH$$_3$$? (Molar mass of NH$$_3 = 17.03 g/$$mol)

Accepted Answer

$$0.75 	imes 17.03 = 12.77 g$$

Question 4

Which of the following is NOT a property of ionic compounds?

Accepted Answer

Conduct electricity in solid form

Question 5

Which of the following elements is diatomic in its elemental form?

Accepted Answer

Nitrogen

Question 6

Which of the following shows the correct Lewis dot notation for carbon?

Accepted Answer

IV

Question 7

What is the correct name for the compound Pb(SO$$_4$$)$$_2$$?

Accepted Answer

Lead (IV) sulfate

Question 8

How many oxygen atoms are in the compound Mg$$_3(PO$_4$$)$$_2$$?

Accepted Answer

8

Question 9

Which of the following acids is correctly paired with its anion?

Accepted Answer

Hydroiodic acid – I$$^-$$

Question 10

A sample of gas in a fixed volume container is heated. What happens to the pressure, velocity, and mass of the gas?

Accepted Answer

Pressure increases, velocity increases, mass remains the same

Question 11

Which of the following is NOT part of the kinetic molecular theory of gases?

Accepted Answer

There is very little empty space in a gas.

Question 12

What is the total pressure in atmospheres of a gas mixture containing O$$_2 at 3.00 $$atm, Ne at 845 mm Hg, and CO$$_2 at 459 $$torr? (1 atm = 760 mm Hg)

Accepted Answer

4.72 atm

Question 13

Which answer choice gives the molecular shape with its correct bond angle?

Accepted Answer

Bent / 109.5$$^\circ$$

Question 14

How many moles of O$$_2$$ are produced if 3.2 moles of H$$_2O$_2$$ decompose according to the equation: $$2\,\mathrm{H_2O_2} \rightarrow 2\,\mathrm{H_2O} + 1\,\mathrm{O_2$}$$?

Accepted Answer

1.6 moles

Question 15

Which of the following is NOT a property of metals?

Accepted Answer

Soluble in water

Question 16

Which of the following prefixes indicates 7 atoms of an element in a molecular compound?

Accepted Answer

Hepta-

Question 17

What is the molar mass of (NH$$_4$$)$$_3PO$_4$$?

Accepted Answer

149.1 g/mol

Question 18

Which of the following acids is correctly named according to the rules for ternary acids?

Accepted Answer

HNO$$_2$$ – Nitrous acid

Question 19

Which of the following is the correct formula for dinitrogen tetrasulfide?

Accepted Answer

N$$_2S$_4$$

Question 20

Which statement about polyatomic ions is true?

Accepted Answer

They have covalent bonding.

Comprehensive Study Guide: Moles, Compounds, Stoichiometry, Gases, and Acids/Bases

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