GENERAL CHEMISTRY II, CH 222 4 credits, CRN 21308 Winter 2016
Department of Chemistry & Biochemistry, University of Oregon
COURSE SYLLABUS
Instructor:
Prof. Thomas J. Greenbowe, Ph.D.
Office: Room 177 Onyx Bridge
Office phone: 541-346-2218
e-mail: tgreenb
1.25
g = (100032781. i= 0.82781 i
p: 151111111. mL L
There are 3 signicant digits in 1.25 g and 4 in 1510. mL. That means your calculated value For .1) has 3 signicant
digits. But keep two extra for now, and only round the nal answer to the correct number
120.
g 1 =15o4e. tool
45.0534 3 -n1ol-
There are 3 signicant digits in your calculated 1lralue for the moles of CHECH
answer to the correct number of signicant digits.
Now you can multiply the moles of ethanol by the molar heat of 1lr'aoorization t
k]
)
Atmospheric pressure:
The third force on the mercury is the force exerted on the mercury in the Jtube by the atmosphere. When the end of the
Jtube is openIr air from the atmosphere will enter it and push clown on the mercury. That will make the mercury ow
Calculate the amount of heat needed to melt 11.6 g of ioe (H20) and bring it to a temperature of 69.2 C. Round your answer to 3 signicant digits. Al
be sure your answer oontains a unit symbol.
EXPLANATION
Heat is needed for two reasons in this problem:
1
A sample of an unknown compound is vaporized at 209. C. The gas produced has a volume of1510. mL at a pressure
of 1.00 aim, and it weighs 1.25 g.
Assuming the gas behaves as an ideal gas under these oonditions, calculate the molar mass of the compound. Ro
2. Heat is needed to raise the temperature of the water.
After the ice is melted, its temperature needs to be raised from its melting temperature (0 "(3) to 69.2 0C, which is a change of
69.2 (30 C = 69.2 C = 69.2 K
The connection between temperature chan
1r L aim
on 11.2 3 0.39986 ml (0.39935 mol)(0.03205?4 mom )cfw_23145 K)
5.0m L 1.3501 atm
L atm
N20 4,5 g 0.1:)111 ml (0.10111 mol)(0.08205?4 mu] K )(233.45 K)
=0.47035 atm
5.000 L
The moles have 3 significant digits, the volume has 3 signicant digits,
A 5.000 L tank at 1(13 C is lled with 11.2 g of carbon monoxide gas and 4.45 g of dinitrogen monoxide gas. You can
assume both gases behave as ideal gases under these conditions.
Calculate the mole fraction and partial pressure of each gas, and the total
It's the equation for p that will let you solve this problem.
FirstIr you'll need to convert the temperature of the sulfur tetrauoride gas to absolute temperature:
T= 10 C=263.15 K
You'll also need the molar mass of SF4:
M: 103.059 L
11101
Now you're read