Chem 167 SI
Exam 1 Review
Ch. 1-5
Leader: Grady
Course: Chem 167
Instructor: Houk
Supplemental Instruction
Iowa State University
Important tables: 2.4, 2.5, 2.6, 2.7, 3.1, 3.2
Date: 2/2/15
1. Complete the table below with the correct number of protons, neutrons and electrons
# of protons
# of neutrons
# of electrons
85
Rb
_______
_______
_______
27
Al3+
_______
_______
_______
_______
_______
_______
16 2-
O
2. Calculate the molar mass of these organic compounds. Draw the molecular structure also
and do not worry about sig figs:
a. Carboxylic acid with a ketone and 4 carbons
b. Alkene with 3 carbons
3. Give the following answer to the correct number of significant figures:
[(12.67+19.2)∗ 3.99]
1.367
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4. Rubidium has two naturally occurring isotopes, 85Rb (relative mass 84.9118 amu) and
87
Rb (relative mass 86.9092 amu). If rubidium has an average atomic mass of 85.47 amu,
what is the abundance of each isotope (in percent)?
5. Balance the following equation and give the net ionic equation:
𝐾3 𝑃𝑂4 (𝑎𝑞) + 𝐴𝑙(𝑁𝑂3 )3 (𝑎𝑞) → 𝐾𝑁𝑂3 (𝑎𝑞) + 𝐴𝑙𝑃𝑂4 (𝑠)
6. The elemental analysis of a compound is 37.5 %C, 12.6 %H, and 49.9 %O. What is the
empirical formula of compound? What is the molecular formula if the compound has a
molecular weight of 128.2 g/mol?
7. Hydrazine, N2H4, is a weak base and can react with an acid such as sulfuric acid:
2N2O5(aq) + H2SO4(aq)  2N2H5+(aq) + SO42-(aq)
What mass of hydrazine can react with 250. mL 0.225M H2SO4? How many molecules
of hydrazine react?
8. Give the formula for the following compounds:
a. Lithium sulfate
b. Berylium phosphide
c. Dinitrogen monoxide
9. Name the following compounds:
a. 𝐹𝑒𝑆𝑂4
b. 𝐾2 𝑆
c. 𝑃2 𝑂5
10. If 15 grams of copper (II) chloride react with 25. grams of sodium nitrate to produce
sodium chloride and copper (II) nitrate, how much sodium chloride can be formed? What
is the limiting reactant? If 11.3 grams of sodium chloride are formed in the reaction, what
is the percent yield? Write the balanced chemical reaction (Neglect writing the states in
the reaction).
11. N2O5 is an unstable gas that decomposes according to the following reaction:
2𝑁2 𝑂5 (𝑔) → 4𝑁𝑂2 (𝑔) + 𝑂2 (𝑔)
What would be the total pressure of gases present if a 10.0L container at 22.0 oC begins
with 0.400 atm of N2O5 and the gas completely decomposes?
12. Calculate the pressure of 15.0 g of methane (CH4) gas in a 1.50 L vessel at 45.0° C using
(a) the ideal gas law and (b) the van der Waals equation using constants from Table 5.2
(a=2.253 atm L2 mol-2 b=0.04278 L mol-1)
13. When 0.684 g of an organic compound containing only C, H, and O was burned in
oxygen 1.312g CO2 and 0.805g H2O were obtained. What is the empirical formula of the
compound?