Question

A football at 27 degree Celsius has 0.5 mole of air molecules. Calculate the internal energy of air in the ball​

Answer 1

Given info : A football at 27 degree Celsius has 0.5 mole of air molecules.

To find : The internal energy of air in the ball is ..

solution : temperature of football, T = 27°C = (27 + 273)K = 300K

no of moles of air molecules in football, n = 0.5

internal energy of ideal gas is given by, U = 3/2 nRT

= 3/2 × 0.5 × 25/3 × 300 K [ value of R = 25/3 J/mol/K]

= 0.25 × 25 × 300 J

= 6.25 × 300 J

= 1875 J

= 1.875 kJ

Therefore the internal energy of air in the ball is 1.875 kJ