Question

Calculate delta Gº for the following system:

delta H = -472 kJ/mol
delta S = -108 J/molk

answer is supposed to be 440 kj, but I have no clue how to get there​

Answer 1

Answer:

ΔG = - 442.5  KJ/mol    

Explanation:

Data Given

delta H = -472 kJ/mol

delta S = -108 J/mol K

So,

delta S = -0.108 J/mol K

delta Gº = ?

Solution:

The answer will be calculated by the following equation for the Gibbs free energy

                    G = H - TS

Where

G = Gibbs free energy

H = enthalpy of a system (heat

T = temperature

S = entropy

So the change in the Gibbs free energy at constant temperature can be written as

                ΔG = ΔH - TΔS . . . . . . (1)

Where

ΔG = Change in Gibb’s free energy

ΔH = Change in enthalpy of a system

ΔS = Change in entropy

if system have standard temperature then

T = 273.15 K

Now,

put values in equation 1

                  ΔG = (-472 kJ/mol) - 273.15 K (-0.108 KJ/mol K)

                 ΔG = (-472 kJ/mol) - (-29.5 KJ/mol)

                 ΔG = -472 kJ/mol + 29.5 KJ/mol

                 ΔG = - 442.5  KJ/mol