Chem 130.999
Exam Ch.1,2,3
Key Begins on page 5.
YOU MUST SHOW ALL WORK FOR CREDIT.....NEATLY......WITH UNITS.
1. To how many significant figures should the following calculation be reported?
0.08206 x (273.15+1.2)
1.23 x 7.004
a) 2
b) 3
c) 4
d) 5
e) 6
2. Indicate the number of significant figures in each of the following.
a) 9.807
b) 0.0082300
_______
_______
c) 1.60 x 10-6
_______
d) 10.500
_______
3. Complete the following.
a) 250 ms = ______________ms
c) 1.49 cm = _______________ dm
b) 28.35 grams = ___________kg
d) 90 oC = _______________K
4. Express the following measurements in scientific notation.
a) 186,000 miles/sec (the speed of light)
________________
b) 0.000000002 K (the lowest temp ever recorded)
________________
c) 1/100,000,000 meters
________________
d) 0.000000535 meters (the approximate wavelength of green light)
________________
5. The distance for a marathon is 26 miles and 185 yards. Convert this distance to kilometers (1 mile = 1760
yards).
________________________km
6. Express the volume in milliliters of a "1.00-cup" sample of milk given that 2 cups = 1 pint, 2 pints = 1 quart.
__________________________mL
7. An international committee of distinguished scientists met to establish the standard "snail's pace", Psn. The
average snail covered 1.00 inch in 3.00 minutes. Express the average Psn in cm/sec.
______________cm/sec
8. The temperature on the night-side of the lunar surface is -193oC. Express this temperature in oF and
in Kelvin.
__________oF
__________K
9. Popcorn is sold by the pound. Given an average mass per kernel of 0.115 g., how many kernels are there in
a pound of popcorn?
_____________________kernels
10. When a piece of metal of mass 5.60 grams is dropped into a graduated cylinder containing 8.3 mL of water,
the water level rises to 10.8 mL. What is the density of the metal in g/cm3?
_______________g/cm3
11. A supersonic transport (SST) airplane consumes about 6,000 gallons of kerosene per hour of flight.
Kerosene has a density of 0.955 g/mL. What mass (in kg) of kerosene is consumed on a flight that takes 3.0
hours? (1 gallon = 4 quarts)
________________kg
12. Indicate whether each of the following are considered to be physical changes or chemical changes.
a) the rusting of iron.
_________________________
b) milk turning sour.
_________________________
c) tearing paper.
_________________________
d) Aluminum foil melts at 933K
_________________________
13. Give the symbols for:
a) three transition metals_______________________
c) a noble gas_______________________
b) a halogen
d) an alkali metal_____________________
_______________________
14. Complete the following table.
Atomic
Number
Mass
Number
Protons
Neutrons Electrons Name
18
Symbol
18
34
18
42
K
15. Gallium has two naturally occuring isotopes, Ga-69 and Ga-70, with masses of 68.9257 amu and 70.9249
amu, respectively. Calculate the percent abundance of each of these isotopes given that the reported mass
for gallium is 69.7233 amu.
%Ga-69 = _____________
%Ga-70 = ______________
16. Indicate whether the following compounds are ionic or covalent.
a) CaF2
b) OCl2
_______________________
_______________________
c) NaO ________________________
d) CF4 ________________________
17. What charges are most commonly observed for ions of the following elements?
a) Potassium
_______
c) Nitrogen
_______
b) Sulfur
_______
d) Oxygen
_______
18. Give names for the following ionic compounds.
a) (NH4)2SO4 ____________________ c) Ca(ClO4)2 ______________________
b) Co3(PO4)2 ____________________
d) PbCr2O7
______________________
19. Give formulas for each of the following ionic compounds.
a) nickel(II)thiosulfate
________________
c) calcium chromate
______________
b) calcium oxalate
________________
d) strontium chloride
______________
20. Give names or formulas for the following covalent compounds.
a) XeF6 _________________________ c) SiS2 ____________________________
b) dinitrogen tetrafluoride _____________ d) tetraphosphorus decoxide __________
21. Balance the following equations.
a) _______C6H5CH3(l) + _______O2(g)
b) _______Fe(s) + _______H2O(g)
_______CO2(g) + _______H2O(l)
_______Fe2O3(s) + _______H2(g)
c) _______Ba(NO3)2(s) + _______Na3P(aq)
d) _______Pb(OH)2(s) + _______HCl(aq)
_______Ba3P2(s) + _______NaNO3(aq)
_______PbCl2(s) + _______H2O(l)
USE THE FOLLOWING EQUATION TO ANSWER QUESTIONS 22-25
5 H2C2O4(aq) + 2 KMnO4(aq) + 6 HCl(aq)
Mm(g/mol) =(90.0)
(158.0)
(36.5)
2 KCl(aq) + 2 MnCl2(aq) + 10 CO2(g) + 8 H2O(l)
(74.6)
(125.9)
(44.0)
(18.0)
22. Calculate the number of moles of CO2 produced by the complete reaction of 15 moles KMnO4.
______________mol CO2
23. Calculate the number of grams of water produced by the complete reaction of 250.0 grams H2C2O4.
(assuming all other reactants are in excess).
______________g H2O
24. If 150.0 grams each of H2C2O4 , KMnO4 , and HCl react , indicate which reactant is the limiting reagent.
______________
25. If 300.0 g H2C2O4 reacts completely to produce only 45.0 g MnCl2, calculate the percent yield of the
reaction.
_______________%
Extra Credit
The aluminum in a package containing 75 ft2 of kitchen foil weighs approximately 12 ounces. Aluminum has a
density of 2.70 g/cm3. What is the approximate thickness of the aluminum foil in mm? (1 ounce = 28.4 grams)