Chem 10113, Exam 1
Name:
September 24, 2014
(Please Print)
1.
Write the complete symbol of the specific atom or ion that has 27 electrons, 36 neutrons,
and a mass number of 65.
2.
(5 points)
3.
(8 points)
4.
SHOW ALL WORK. Tartaric acid is the white powdery substance that coats sourtasting candies such as Sour Patch Kids. Combustion analysis of a 1.20 g sample of tartaric acid
(which contains only C, H, and O) produced 1.41 g of CO2 and 0.432 g of H2O. Determine the
empirical formula of tartaric acid. (molar masses: CO2 = 44.0, H2O = 18.0)
(3 points)
Balance the following chemical equations.
(a) _____ Al2O3 + _____ C → _____ Al4C3 + _____ CO
(b) _____ NH3 + _____ O2 → _____ NO + _____ H2O
SHOW ALL WORK. An unknown compound of molecular mass 171 contains only
carbon, hydrogen, and bromine. Analysis shows that the compound contains 12 times as much
carbon as hydrogen by mass. Determine the molecular formula of the compound.
(12 points)
5
(19 points)
Write the chemical formula for each of the following compounds.
Name
Formula
lead(IV) acetate
aluminum oxalate
chromic acid
cobalt(II) phosphate octahydrate
ammonium sulfite
mercury(I) cyanide
hydrosulfuric acid
hexane
rubidium peroxide
tetraphosphorus heptasulfide
6.
SHOW ALL WORK. When 100.0 mL of 0.360 M Ca(NO3)2 solution is mixed with
200.0 mL of 0.160 M Na3PO4, the following precipitation reaction occurs. The solid Ca3(PO4)2 is
collected, dried, and found to have a mass of 3.15 g. Determine the percent yield of this reaction.
{molar mass: Ca3(PO4)2 = 310.2}
3 Ca(NO3)2(aq) + 2 Na3PO4(aq) → Ca3(PO4)2(s) + 6 NaNO3(aq)
(12 points)
7.
Write a complete, balanced chemical equation for each of the following processes.
(a) (4 points) The addition of nitric acid to water.
(b) (4 points) The preparation of barium perchlorate by a neutralization reaction.
(c) (4 points) The combustion of acetone, (CH3)2CO.
8.
In each of the following organic molecules, circle the main functional group and write the
appropriate family name (i.e., alkane, alcohol, etc.) below each one.
(8 points)
H3C
CH3
N
9.
O
O
CH3O C CH2CH3
C CH
H
C CH CH3
CH2CH3
Complete the following statements for the substance Na2B12H12. (Work need not be
shown!) This substance has a molar mass of _____________ g/mole and is __________ % boron
(8 points)
by mass. The empirical formula of this substance is ____________________. The number of
boron atoms in 0.25 mole of Na2B12H12 is __________________.
10. (5 points) Circle any of the following that are molecular compounds.
HSF3
AlPO4
HN3
KrF2
TeF4
NH4Br
Li2O2
SnS2
11. (8 points) SHOW ALL WORK. A crisp, new $100 bill weighs almost exactly 1.00 g. A typical 18wheeler has a hauling capacity of 24 tons. The next time that you pass a truck like that on the
highway, imagine it packed to full capacity with new $100 bills. (That's a lot of money, right?!?!)
The US national debt is currently 17.8 trillion dollars (i.e., 17.8 teradollars!). Determine the
number of trucks, every one packed full of $100 bills, that would be required to carry the national
debt. (Note: You must use the factor-label method to receive credit for your work.)