Summer 07 Chem 100 Ch 8.6-9 100 Pts
Name ____________________________
For Full Credit, show all of your work work
Hints: 1 atm = 760 mmHg, 1 mmHg = 1 torr, study hard
Part 1: Choose the Single closest or best answer. 5 pts each
1. How many moles of gas are present in a 10.0 liter sample at STP?
A) 224 moles
B) 22.4 moles
C) 10.0 moles
D) 2.24 moles
E) 0.446 moles
2. How many grams of O2 are contained in a 25.0 L sample at 5.2 atm and 28.0°C?
A) 1810 g
B) 168 g
C) 84.2 g
D) 5.26 g
E) 0.164 g
3. Calculate the volume of 5.00 mol of helium (m.w. 4 g/mol) at 120°C and 1520 mm Hg.
A) 323 liters
B) 80.7 liters
C) 0.106 liters
D) 0.0324 liters
E) none of the above
4. What is the total pressure of a mixture of He (m.w. 4 g/mol) and H2 (m.w. 2 g/mol) if the partial
pressures are 320 mm Hg and 800 mm Hg respectively?
A) 40 mm Hg
B) 60 mm Hg
C) 320 mm Hg
D) 480 mm Hg
E) 1120 mm Hg
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