Chemistry 101

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Are these correct?
1. A sample of gases contains three gases at the following pressures: 1.2 atm N2, 3.2 atm O2, and 0.56 atm Xe. What is the total pressure in the container?
a. 5.0atm
b. 1.4atm
c. 2.2atm
d. 1.0atm
e. 1.7atm
I am pretty sure it is A. Is that correct?

2. The molar volume of a gas at STP
a. is always 22.4L
b.varies with the type of gas
c. is dependent upon the temperature and pressure of the gas
d. is directly proportional to the molar mass of the gas
e. is always 6.02 x 1023 L
I think this one is A as well.

• Chemistry 101 -

Those look ok to me.
On 1, remember that Dalton's Law of Partial Pressure says that the total pressure is the sum of all of the partial pressures; therefore, 3.2 + 1.2 + 0.56 = 4.96 atm. Then significant figures comes into play. When adding, the answer may contain only to the tenths place; thus, 4.96 rounds to 5.0 atm.

• Chemistry 101 -

Thank you Dr Bob!!!!

• Chemistry 101 -

the valve between a 3.00-L tank containing O2(g) at 6.00 atm. and a 5.00-L containing N2(g) at 1.20 atm. is opened. Calcualte the ratio of partial pressures (O2:N2) in the container?