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A 4.5 L sample of a gas was collected over water on a day when the temperature was 24◦C and the barometric pressure was 706 torr. The dry sample of gas had a mass of 5.6 grams. What is the mass of three moles of the dry gas? At 24◦C the vapor pressure of water is 22 torr. Answer in units of g

User Igand
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1 Answer

4 votes

Answer:

19.02 g

Step-by-step explanation:

dry gas mass of 3 moles of the

1. find out the identity of the gas

ideal gas law:

PV = nRT

where P is the pressure, V is the volume, n is the number of moles, R is the gas constant, and T is the temperature.

First, we need to correct for the water vapor present in the gas sample. At 24◦C, the vapor pressure of water is 22 torr, so the total pressure in the sample is:

Ptotal = Pgas + Pwater vapor

706 torr = Pgas + 22 torr

Pgas = 684 torr

ideal gas law to get the number of moles of gas

n = PV/RT

where we use the corrected pressure and the temperature in Kelvin:

n = (684 torr x 4.5 L) / (0.0821 L·atm/mol·K x 297 K)

n = 0.883 mol

calculate the molar mass of the gas:

molar mass = mass / n

molar mass = 5.6 g / 0.883 mol

molar mass = 6.34 g/mol

calculate the mass of three moles of the gas:

mass = n x molar mass

mass = 3 mol x 6.34 g/mol

mass = 19.02 g

Therefore, the mass of three moles of the dry gas is 19.02 g

chatgpt

User Oleksandr Mosur
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