Question

.
One mole of methane undergoes combustion to form CO2, and water at 25°C. The difference between
AU and AH will be
1)-2RT
2) 3RT
3) RT
4) 0​

Answer 1

Answer:

The answer is 1)-2RT.

Hope it is clear.

Answer 2

-2RT

METHANE COMBUSTION:

It is feasible to burn methane since it is combustible. This combustion process is chemically defined as a reaction between methane and oxygen in the air. When this reaction occurs, carbon dioxide (CO2), water (H2O), and a lot of energy are produced.

Combustion of methane:

$CH_{4}$(g)+$2O_{2}$(g) ⇒ $CO_{2}$(g) + 2$H_{2} O$ (l)

$n_{g}$ - number of moles of gaseous products

     = 1-3

     = -2

Formula,

ΔH= ΔU + $n_{g}$RT

Difference between ΔH and ΔU = $n_{g}$ RT

$n_{g}$ = -2

ΔH-ΔU= -2RT

Answer 3

The difference between ΔH and ΔU will be 2RT

• We know that the relation between ΔH and ΔU is as follows:

                                            ΔH= ΔU +nRT

Where, n = moles of gaseous product - moles of gaseous reactants

• The reaction for the combustion of methane is as follows:

                             CH₄(g) + 2O₂(g) → CO₂(g) + 2H₂O

n = 1-3 = -2

ΔH= ΔU +(-2RT)

Thus, the difference between ΔH and ΔU will be (Option 1) -2RT.