In: Chemistry
A 1.0 m3 tank, initially filled with 103. kPa, 300. K air, is connected to a source of air at 1,500. kPa, 300. K. The tank slowly fills until it is at the same pressure. If the temperature is maintained at 300. K throughout this transient process, what is the total heat transfer required? (You can assume air is an ideal gas.)
Answer – Given, volume, V = 1.0 m3, P1 = 103.0 kPa, P2 = 1500.0 kPa , T = 300 K
And we need to calculate the total heat transfer required
From the give data we can calculate the work using the formula
W = -deltan*RT*lnP1/P2)
We need to calculate moles first
We need to volume in L
So, 1.0 m3 = 1000 dm3 = 1000 L
P in atm –
1 kPa = 0.00987 atm
So, 103 kPa = ?
= 1.02 atm
Now using the Ideal gas law
n = PV/RT
= 1.02 atm*1000 L / 0.0821* 300 K
= 41.4 moles
Moles of air –
P = 1500 kPa = 14.78 atm
n = 14.8 atm*1000 L / 0.0821* 300 K
= 600.9 moles
Deltan =600.9 -41.4 = 559.5 moles
So work
w = - 559.5 * 8.314 J/mol.K * 300 K * ln 103/1500
= 1.246*104 J
We are given constant temperature, so ΔE = 0
Then w = -q
So, heat , q = -w
= - 1.246*104 J
The total heat transfer required is - 1.246*104 J