# Chemistry

A 32.0 mL sample of hydrogen is collected over water at 20.0 degrees celcius and 750.0 torr. What is the volume of the dry gas at STP?

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1. I forgot to add-- Vapor pressure of water at 20.0 degrees celcius is 17.5 torr.

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2. (P1V1)/T1 = (P2V2/T2)
P1 = 750 torr - vapor pressure H2O @ 20 degrees Celsius (note the correct spelling of Celsius).
V1 = 32 mL
T1 = change C to Kelvin.
P2 and T2 are STP; i.e., 760 torr and 273 K.
Post your work if you get stuck.

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3. What do you mean by P1, meaning 750 torr - vapor pressure H2O @ 20 degrees Celsius?

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4. 750 torr - 17.5 torr = ?? torr = P1.
According to Dalton's Law of Partial Pressure, the total pressure is the sum of the partial pressures in the gas.
P(gas) + P(water) = total P = 750 torr. That's what you started with in the problem.

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5. i don't understand the P2 and T2 part with the STP

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6. No

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7. 29.4 mL

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