Name: _________________________
Date: ____________
Period: _______
AP Chemistry – OHS – Chapter 2B Practice
Mr. Daniel
Reviewing Important Concepts
1. A model of the cancer chemotherapy agent cisplatin is given here. How many N atoms are in
one molecule? How many H atoms occur in one molecule? How many H atoms are in 1 mol of
the compound? What is its molar mass?
3. a) How many electrons are in a strontium atom (Sr)?
b) Does an atom of Sr gain or lose electrons when forming an ion?
c) How many electrons are gained or lost by the atom?
d) When Sr forms an ion, the ion has the same number of electrons as which one of the
noble gases?
7. Which has the larger mass, 0.5 mol of BaCl2 or 0.5 mol of SiCl4?
Practice Skills
Molecular Formulas
10. Write the molecular formula of each of the following compounds:
(a) An organic compound, heptanol, has 7 carbon atoms, 16 hydrogen atoms, and 1 oxygen
atom.
(b) Vitamin C, ascorbic acid, has six carbon atoms, eight hydrogen atoms, and six oxygen
atoms per molecule.
(c) A molecule of aspartame, an artificial sweetener, has 14 carbon atoms, 18 hydrogen
atoms, 2 nitrogen atoms, and 5 oxygen atoms.
12. Give the total number of atoms of each element in one formula unit for each of the following
compounds:
(a) CaC2O4
(b) C6H5CHO
(c) K4Fe(CN)6
Molecular Models
Ions & Ion Charges
16. What charges are most commonly observed for monatomic ions of the following elements?
(a) Magnesium
(c) Nickel
(b) Zinc
(d) Gallium
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18. Give the symbol, including the correct charge, for each of the following ions:
(a) Barium ion
(e) Sulfide ion
(b) Hydrogen carbonate ion
(f) Titanium(IV) ion
(c) Phosphate ion
(g) Perchlorate ion
(d) Cobalt(II) ion
(h) Sulfate ion
20. a) When potassium becomes a monatomic ion, how many electrons does it lose or gain?
b) What noble gas atom has the same number of electrons as a potassium ion?
Ionic Compounds
24. For each of the following compounds, give the formula, charge, and number of each ion that
makes up the compound:
(a) K2S
(b) CoSO4
(c) KMnO4
(d) (NH4)3PO4
(e) Ca(ClO)2
26. Cobalt is a transition metal and forms ions with at least two different charges. Write the
formula for the two different cobalt oxides.
28. Which of the following are the correct formulas for ionic compounds? For those that are not,
give the correct formula.
(a) AlCl2
(b) KF2
(c) Ga2O3
(d) MgS
30. Write all of the formulas for the compounds that can be made by combining the cations Mg2+
and Al3+ with the anions O2− and PO43−.
Naming Ionic Compounds
32. Name each of the following ionic compounds:
(a) K2S
(b) CoSO4
(c) (NH4)3PO4
(d) Ca(ClO)2
34. Give the formula for each of the following ionic compounds:
(a) Ammonium carbonate
(b) Calcium iodide
(c) Copper(II) bromide
(d) Aluminum phosphate
(e) Silver(I) acetate
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Coulomb’s Law
38. Sodium ion, Na+, forms ionic compounds with fluoride, F−, and iodide, I−. You know that the
radii of these ions are: Na+ = 116 pm; F− = 119 pm; and I− = 206 pm. In which compound,
NaF or NaI, are the forces of attraction between cations and anions stronger? Explain your
answer.
Naming Binary, Nonmetal Compounds
40. Give the name for each of the following binary, nonionic compounds:
(a) NF3
(b) HI
(c) BI3
(d) PF5
42. Give the formula for each of the following nonmetal compounds:
(a) Sulfur dichloride
(b) Dinitrogen pentaoxide
(c) Silicon tetrachloride
(d) Diboron trioxide (commonly called boric oxide)
Molecules, Compounds, and the Mole
44. Calculate the molar mass of each of the following compounds:
(a) Fe2O3 (iron(III) oxide)
(b) BCl3 (boron trichloride)
(c) C6H8O6 (ascorbic acid, vitamin C)
46. Calculate the molar mass of each hydrated compound. Note that the water of hydration is
included in the molar mass. (See section 3.7.)
(a) Ni(NO3)2 · 6 H2O
(b) CuSO4 · 5 H2O
48. What amount (moles) is represented by 1.00 g of each of the following compounds?
(a) C3H7OH, propanol, rubbing alcohol
(b) C9H8O4, aspirin
52. Sulfur trioxide, SO3, is made industrially in enormous quantities by combining oxygen and
sulfur dioxide, SO2.
a) What amount of SO3 (moles) is represented by 1.00 kg of sulfur trioxide?
b) How many molecules would that be?
c) How many sulfur atoms?
d) How many oxygen atoms?
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Percent Composition
54. Calculate the mass percent of each element in the following compounds.
(a) PbS (lead(II) sulfide: also known as the mineral galena)
(b) C3H8 ( propane)
56. Using your answer from question 54a, calculate the mass of lead in 10.0 g of PbS.
58. If you wish to obtain 100.0 g of hydrogen gas from propane (C3H8) what mass of C3H8 must
you start with? (Use your data from question 54b)
Empirical & Molecular Formulas
62. Complete the following chart:
64. Acetylene is a colorless gas used as a fuel in welding torches, among other things. It is
92.26% C and 7.74% H. Its molecular mass is 26.02 g/mol. Calculate the empirical and
molecular formulas of acetylene.
68. Mandelic acid is an organic acid composed of carbon (63.15%), hydrogen (5.30%), and
oxygen (31.55%). Its molecular mass is 152.14 g/mol. Determine the empirical and molecular
formulas of the acid.
70. If Epsom salt, MgSO4· x H2O, is heated to 250°C, all the water of hydration is lost. On
heating a 1.687-g sample of the hydrate, 0.824 g of MgSO4 remains. How many molecules of
water occur per formula unit of MgSO4?
72. A new compound containing xenon and fluorine was formed by shining sunlight on a mixture
of 0.526 g Xe and excess F2 gas. If 0.678 g of the new compound was produced, what is its
empirical fomula?
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