# Chemistry

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Three of the primary components of air are carbon dioxide, nitrogen, and oxygen. In a sample containing a mixutre of only these gases at exactly one atmosphere pressure, the partial pressure of carbon dixoide and nitrogen are given as Pco2 = 0.285torr and Pn2=593.525torr. What is the partial pressure of oxygen?

Okay, I tried working this one, and all I can get out of this problem is

0.285+593.525= 593.810torr
I need help

Determine the partial pressure of oxygen collected by water displacement if the water temperature is 20.0C and the total pressure of the gas in the collection bottle is 730 torr.

Po2=712.5torr <-- is that right?

A sample of gas is collected over water at a temperature of 35.0C when the barometric pressure reading is 742.0 torr. What is the partial pressure of the dry gas?

I got 699.8torr for the dry gas

A sample of oxygen is collected in a 175mL container over water at 15C, and the barometer reads 752.0 torr. What volume would the dry gas occupy at
770.0 torr and 15C

I'm thinking this has to do something with Boyles law? I need help.

Suppose that 120.mL of argon is collected over water at 25C and 780.0 torr. Compute the volume of the dry argon at STP.

Would this be involved with Charles law?

• Chemistry - ,

Three of the primary components of air are carbon dioxide, nitrogen, and oxygen. In a sample containing a mixutre of only these gases at exactly one atmosphere pressure, the partial pressure of carbon dixoide and nitrogen are given as Pco2 = 0.285torr and Pn2=593.525torr. What is the partial pressure of oxygen?

Okay, I tried working this one, and all I can get out of this problem is

0.285+593.525= 593.810torr
I need help
Dalton's law says that the total pressure is the sum of the partial pressures.

Determine the partial pressure of oxygen collected by water displacement if the water temperature is 20.0C and the total pressure of the gas in the collection bottle is 730 torr.

Po2=712.5torr <-- is that right?

yes

A sample of gas is collected over water at a temperature of 35.0C when the barometric pressure reading is 742.0 torr. What is the partial pressure of the dry gas?

I got 699.8torr for the dry gas
yes. Watch the number of significant figures if your prof is picky about that, although I think you are allowed 4 in this problem.

A sample of oxygen is collected in a 175mL container over water at 15C, and the barometer reads 752.0 torr. What volume would the dry gas occupy at
770.0 torr and 15C

I'm thinking this has to do something with Boyles law? I need help.

Use PV=nRT or (P1V1/T1) = (P2V2/T2)

Suppose that 120.mL of argon is collected over water at 25C and 780.0 torr. Compute the volume of the dry argon at STP.

Would this be involved with Charles law?
(P1V1/T1) = (P2V2/T2)
Don't forget to use T in Kelvin. Subtract the vapor pressure of water from the total pressure for this problem as well as the previous one.