Two moles of ideal helium gas are in a rubber balloon at 30°C. The balloon is fully expandable and can be assumed to require no energy in its expansion. The temperature of the gas in the balloon is slowly changed to 35°C. The amount of heat required in raising the temperature is nearly (take R = 8.31 J/mol-K.)

Question

Two moles of ideal helium gas are in a rubber balloon at 30°C. The balloon is fully expandable and can be assumed to require no energy in its expansion. The temperature of the gas in the balloon is slowly changed to 35°C. The amount of heat required in raising the temperature is nearly (take R = 8.31 J/mol-K.) (A) 62 J (B) 104 J (C) 124 J (D) 208 J

Tardigrade Admin · Accepted Answer

The process may be assumed to be isobaric. ∴ Q=nCP Δ T =(2) ((5/2)R)(5) = 5 × 8.31 × 5 =207.75 J =208 J

62 J

104 J

124 J

208 J

The process may be assumed to be isobaric. ∴Q=nCP​ΔT=(2)(25​R)(5) =5×8.31×5=207.75J=208J

The process may be assumed to be isobaric.
$∴ Q = n C_{P} Δ T = (2) (\frac{5}{2} R) (5)$
= $5 \times 8.31 \times 5 = 207.75 J = 208 J$