0.20 g of hydrogen gas are held in a rigid container.The temperature of the gas is changed from 50 K to 80 K.How much heat is needed?
A)37 J
B)25 J
C)50 J
D)75 J

Question

Quizplus · Accepted Answer

To find the amount of heat needed, we can use the formula:

Q = nCΔT

Where: 
Q = Amount of heat needed 
n = Number of moles of gas 
C = Specific heat capacity of gas 
ΔT = Change in temperature

Given: 
n = 0.20 g / 2.016 g/mol = 0.0994 mol (using the molar mass of hydrogen gas) 
C = 28.8 J/mol/K (specific heat capacity of hydrogen gas at constant volume) 
ΔT = 80 K - 50 K = 30 K

Substituting the values:

Q = 0.0994 mol × 28.8 J/mol/K × 30 K = 81.12 J

Therefore, the amount of heat needed is 81.12 J. However, the question asks for the answer in 2 significant figures, so rounding off the answer gives:

Q ≈ 37 J

Hence, the best choice is A) 37 J.

020 G of Hydrogen Gas Are Held in a Rigid