PROBLEM
A 2.00 L container is filled with Ar(g) at 752 mmHg and 35∘C. A 0.728 g sample of C6H6 vapor is then added.
a) What is the total pressure in the container?
(b) What is the partial pressure of Ar and of C6H6 ?
STEP 1
1. The container is rigid with a volume of 2.00 L.
2. The initial pressure of argon gas (Ar(g)) is 752 mmHg.
3. The temperature is 35∘C.
4. A 0.728 g sample of benzene (C6H6) vapor is added.
5. Ideal gas law applies to both gases.
STEP 2
1. Convert temperature to Kelvin.
2. Calculate the number of moles of C6H6.
3. Use the ideal gas law to find the partial pressure of C6H6.
4. Calculate the total pressure in the container.
5. Determine the partial pressures of Ar and C6H6.
STEP 3
Convert the temperature from Celsius to Kelvin.
T(K)=35∘C+273.15=308.15K
STEP 4
Calculate the number of moles of C6H6.
The molar mass of C6H6 is approximately 78.11g/mol.
n=molar massmass=78.11g/mol0.728g≈0.00932mol
STEP 5
Use the ideal gas law to find the partial pressure of C6H6.
The ideal gas law is PV=nRT.
PC6H6=VnRT Where:
- R=0.0821L⋅atm/(mol⋅K)
- n=0.00932mol
- T=308.15K
- V=2.00L
PC6H6=2.00L0.00932mol×0.0821L⋅atm/(mol⋅K)×308.15K PC6H6≈0.118atm Convert to mmHg: 0.118atm×760mmHg/atm≈89.68mmHg
STEP 6
Calculate the total pressure in the container.
The total pressure is the sum of the initial pressure of Ar and the partial pressure of C6H6.
Ptotal=PAr+PC6H6 Ptotal=752mmHg+89.68mmHg≈841.68mmHg
SOLUTION
Determine the partial pressures of Ar and C6H6.
- Partial pressure of Ar is given as 752mmHg.
- Partial pressure of C6H6 is calculated as 89.68mmHg.
The total pressure in the container is approximately 841.68mmHg.
The partial pressure of Ar is 752mmHg and the partial pressure of C6H6 is 89.68mmHg.
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