Question

what is the internal energy of 7.00 mol of n2 gas at 40c?

a) 18,200j
b) 5820j
c) 45,500j
d) 11,600j

Answer 1

To find the internal energy of gas we can use

$U = \frac{f}{2}nRT$

here given that

Number of moles (n) = 7 moles

Temperature T = 40 + 273 = 313 K

degree of freedom(f) = 5 (for diatomic gas)

now by above formula

$U = \frac{5}{2}* 7 * 8.31 * 313$

$U = 45518.03 J$

So it is approximately 45500 J (option C)