The standard internal energy change for a reaction can be symbolized as δ u ∘ rxn or δ e ∘ rxn . for each reaction equation, calculate the energy change of the reaction at 25 ∘ c and 1.00 bar . sn ( s ) + 2 cl 2 ( g ) ⟶ sncl 4 ( l ) δ h ∘ rxn = − 511.3 kj/mol

Answer : The internal energy change is, -506.3 kJ/mol

Explanation :

Formula used :

or,

where,

= change in enthalpy =

= change in internal energy = ?

= change in moles

Change in moles = Number of moles of product side - Number of moles of reactant side

According to the reaction:

Change in moles = 0 - 2 = -2 mole

That means, value of = 0

R = gas constant = 8.314 J/mol.K

T = temperature =

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

Therefore, the internal energy change is -506.3 kJ/mol

answer: enthalpy

explanation:

for a exothermic reaction, the energy is released i.e. the energy of the products is lower than the energy of the reactants.

= enthaply

= energy of products

= energy of reactants

as , thus comes out to be negative. negative value of enthalpy shows that the reaction is exothermic.