Final answer:
The energy transferred to a 1.20-mol sample of hydrogen gas heated at constant pressure from 294 K to 424 K is 4.49 kJ.
Step-by-step explanation:
To calculate the energy transferred to the gas by heat, we will use the molar heat capacity at constant pressure (Cp) for hydrogen gas, which is 28.8 J/(mol·K). Since the process occurs at constant pressure, we can use the formula q = nCpΔT, where:
- q is the heat absorbed or released,
- n is the number of moles of gas,
- Cp is the molar heat capacity at constant pressure,
- ΔT is the change in temperature in kelvin.
Given that n = 1.20 mol, ΔT = 424 K - 294 K = 130 K, and Cp = 28.8 J/(mol·K), we find:
q = (1.20 mol)(28.8 J/(mol·K))(130 K) = 4492.8 J
Converting joules to kilojoules by dividing by 1,000, the energy transferred to the gas by heat in kilojoules is:
q = 4492.8 J / 1000 = 4.49 kJ (to two decimal places).