Question

Enter your answer in the provided box. Consider the reaction H2(g) + Cl2(g) → 2HCl(g)ΔH = −184.6 kJ / mol If 2.00 moles of H2 react with 2.00 moles of Cl2 to form HCl, what is ΔU (in kJ) for this reaction at 1.0 atm and 25°C? Assume the reaction goes to completion.

Answer 1

Answer : The value of
`\Delta E` of the reaction is, -369.2 KJ

Explanation :

Formula used :

`\Delta E=\Delta H-\Delta n_g* RT`

where,

`\Delta E` = internal energy of the reaction = ?

`\Delta H` = enthalpy of the reaction = -184.6 KJ/mole = -184600 J/mole

The balanced chemical reaction is,

`H_2(g)+Cl_2(g)\rightarrow 2HCl(g)`

when the moles of
`H_2\text{ and }Cl_2` are 2 moles then the reaction will be,

`2H_2(g)+2Cl_2(g)\rightarrow 4HCl(g)`

From the given balanced chemical reaction we conclude that,

`\Delta n_g` = change in the moles of the reaction = Moles of product - Moles of reactant = 4 - 4 = 0 mole

R = gas constant = 8.314 J/mole.K

T = temperature =
`25^oC=273+25=298K`

Now put all the given values in the above formula, we get:

`\Delta E=(-184600J/mole* 2mole)-(0mole* 8.314J/mole.K* 298K)`

`\Delta E=-369200J`

`\Delta E=-369.2KJ`

Therefore, the value of
`\Delta E` of the reaction is, -369.2 KJ