A container holds 0.800g of oxygen at a pressure of 7.00atm . Part A How much he

Question

A container holds 0.800g of oxygen at a pressure of 7.00atm .

Part A

How much heat is required to increase the temperature by 105?C at constant pressure?

Express your answer with the appropriate units.

98J

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Part B

How much will the temperature increase if this amount of heat energy is transferred to the gas at constant volume?

Express your answer with the appropriate units.

A container holds 0.800g of oxygen at a pressure of 7.00atm .

Part A

How much heat is required to increase the temperature by 105?C at constant pressure?

Express your answer with the appropriate units.

98J

SubmitMy AnswersGive Up

Incorrect; Try Again; 4 attempts remaining

Part B

How much will the temperature increase if this amount of heat energy is transferred to the gas at constant volume?

Express your answer with the appropriate units.

Explanation / Answer

As long as the initial temperature is at least -150 C (most likely), we can model this as an ideal gas.

A) To find the heat transfer required at constant pressure, we can model the change in internal energy + the work done as the gas expands. Or we can use the enthalpy shortcut.

Q = ?U +W
Q = m*?u + P*?V
or
Q = m*?h

Because we assume the gas is calorically perfect,
Q = m*c_p*?T

Oxygen is diatomic, therefore the adiabatic index is k = 1.4. For a particular adiabatic index and molar mass, the mass basis isobaric specific heat is the following:
c_p = R/M * k/(k-1)

Therefore:
Q = m*R*k*?T/(M*(k-1))

Data:
m:=0.7 grams; R:=8.314 J/mol-K; M:=32 g/mole; k:=1.4; ?T:=100 C;

Result:
Q = 63.65 Joules
-----------------------------
B) For constant volume, work is zero. Therefore
Q = ?U

Because we assume the gas is calorically perfect,
Q = m*c_v*?T

For a particular adiabatic index and molar mass, the mass basis isochoric specific heat is the following:
c_p = R/M * 1/(k-1)

Therefore:
Q = m*R*?T/(M*(k-1))

Same data as part A:
Result:
Q = 45.467 Joules

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