Question

The total kinetic energy in joules of the molecules in 8g of methane at 27°c is

Answer 1

KE = (3/2)nRT  where n is the no. of molecules of the gas, R is ideal gas constant and T is temperature in Kelvin.  8g CH4 = 8/16 = 0.5 mol  KE = (3/2)•0.5•8.314•300 KE = 1870.65 J

Answer 2

Answer:

The total kinetic energy of the 8 g methane molecules is 1,871.58 J.

Explanation:

Temperature of the gas = 27 °C = 300.15 K

Moles of methane gas = $\frac{8 g}{16 g/mol}=0.5 mol$

Average Kinetic energy per mole of a gas is given by:

$K.E=\frac{3RT}{2}$

$K.E=\frac{3\times 8.314 J/ mol K\times 300.15 K}{2}=3,743.17 J/mol$

For 0.5 moles of methane, the energy will be:

$0.5 mol\times 3,743.17 J/mol=1,871.58 J$

The total kinetic energy of the 8 g methane molecules is 1,871.58 J.