Question

Five moles of Hydrogen initially at STP is
compressed adiabatically so that its tempera-
ture becomes 673K. The increase in internal
energy of the gas in Kilo Joules is
(R-8.3j/mole-K:=1.4 for diatomic gas)
1) 80.5 2) 21.55 3) 41.50 4) 65.55​

Answer 1

Hi,

Answer:

The increase in internal energy of the gas is 41.50 kJ.

Explanation:

Given data:

No. of moles of hydrogen, n = 5

Initial temperature, T1 = 0℃

Final temperature, T2 = 673K = 673 – 273℃ = 400℃

To find: increase in internal energy, ∆U

The molar heat capacity is given by

Cv = ½ f R

Where f = degree of freedom of the gas and R = 8.3 J/molK

For a diatomic hydrogen gas,

∴Cv = 5R/2  ….. (i)

Now,  

The increase in internal energy of the hydrogen gas,

∆U = n * Cv * ∆T

Or, ∆U

= 5 * 5R/2  * (T2 – T1)  

= 5 * (5 * 8.3 / 2) *(400-0)

= 41500 J

= 41.50 kJ

Hope this helps!!!!!