# Chemistry

posted by .

A sample of gas collected over water at 42 C occupies a volume of one liter. The wet gas has a pressure of 0.986 atm. The gas is dried, and the dry gas occupies 1.04 L with a pressure of 1.00 atm at 90 C. Using this information, calculate the vapor pressure of water at 42 C.

What I have so far:
PV=nrt

n=PV/RT = (1.00 atm)(1.04L)/(0.0821)(363.15K) = 1.04/29.81 = 0.035 mol

• Chemistry -

I think you are right so far although I wouldn't round to 2 s.f. as you did.
I think we know Ptotal = Pdry gas + PH2O = 0.986 atm.

Then we should be able top calculate the P of dry gas at 42 C by using n = 0.0349 moles and substituting the conditions at 42 C. Substitute this Pgas into the Dalton equation above and calculate PH2O. I get something like 63 mm. I found a site on the Internet that listed PH2O @ 42 C as 61.5 mm. Check my thinking.

## Similar Questions

1. ### Chemistry- partial pressures

A sample of gas collected over water at 42 degrees C occupies a volume of one liter. The wet gas has a pressure of .986 atm. The gas is dried and the dry gas occupies 1.04 L with a pressure of 1.00 atm at 90 degrees C. Using this information, …
2. ### chemistry

146 mL of wet H2 gas is collected over water at 29.0 degrees celsius and room pressure of 750 torr. give the volume of the dry H2 gas collected at STP, give the mass of the dry H2 collected, and give the volume of the dry H2 at room …
3. ### Chemistry

A gas occupies a volume of 40 ml at 734.8 mm and 22* C . The gas was collected over water and the water level inside the eudiometer is the same as that outside. What is the volume of dry gas at S.T.P?
4. ### Chemistry

a sample of gas of unknown pressure occupies 0.766 L at the temperture of 298k the same sample of gas is than tested under known conditions and has the pressure of 32.6kPa and occupies 0.664 L at 303 k. What is the original pressure …
5. ### General Chemistry

Answer Check... A 3.00L sample of gas was collected over water at 45 degrees Celsius. The wet gas exerts pressure of 1.50atm. When dried the sample occupies 1.80L and exerts a pressure of 1.77 atm at 80.0 degrees Celsius. What is the …
6. ### Chemistry

A sample of gas is confined to a cylinder housed with a movable piston. Initially, the gas occupies a volume of 2.7 L at 6.0 atm and 25°C. Calculate the volume of the gas sample if the pressure is reduced to 1.8 atm and the temperature …
7. ### chemistry

1)A sample of CO2 gas which weighs 0.85 grams has a volume of 1.30 liters when collected at 30°C. What would be the pressure of the gas sample?
8. ### science

When the metal sample reacts with acid, the gas evolved will be collected over water; the gas is said to be "wet". What is the composition of the wet gas?
9. ### Chemistry

A 40.0 g sample of zinc is allowed to react with excess hydrochloric acid. How many liters of dry hydrogen gas are produced if the gas is collected over water at 23.0 degrees celsius and 1.234 atm of pressure?