Determine the internal energy of 15 mol of a monatomic gas at a temperature of 17 ° C.

Data: ν (amount of substance) = 15 mol; T (absolute gas temperature) = 290 К (17 ºС); a monatomic gas is considered ideal (En = 0).

Constants: R (universal gas constant) = 8.31 J / (mol * K); i (the number of degrees of freedom of molecules of a monatomic gas) = 3.

The internal energy of the gas is determined by the formula: U = Ek = 0.5 * i * ν * R * T.

Let’s make a calculation: U = 0.5 * 3 * 15 * 8.31 * 290 ≈ 54.2 * 10 ^ 3 J (54.2 kJ).

Answer: 15 moles of a monatomic gas have an internal energy of 54.2 kJ.