Calculate Delta G for each reaction using Delta Gf values: answer kJ ...thank you
a) H2(g)+I2(s)--->2HI(g)
b) MnO2(s)+2CO(g)--->Mn(s)+2CO2(g)
c) NH4Cl(s)--->NH3(g)+HCl(g)
is this correct?
a) H2(g)+I2(s)--->2HI(g)
From tables:
G HI = +1.3 kJ/mol
G H2 = 0
G I2 = 0
dG = Gprod - Greact = 2(1.3) = 2.6 kJ/mol
dG = 2.6 kJ/mol
b) MnO2(s)+2CO(g)--->Mn(s)+2CO2(g)
G MnO2 = -465.2
G CO = -137.16
G CO2 = -394.39
G MN = 0
dG = Gprod - Greact = (1(0) + 2*-394.39) - (-465.2 +2*-137.16) = -49.3
dG = -49.3 kJ/mol
c) NH4Cl(s)--->NH3(g)+HCl(g)
HCL = -95.30
NH3 = -16.4
NH4Cl = -203.89
dG = Gprod - Greact = (-203.89) - (-16.4-95.30) = -92.2 kJ/mol
dG = -92.2 kJ/mol
Thank you.
a) 2.6 kJ
b)-49.3 kJ
c) 92.2 kJ
For a the question asks for dG for the rxn so that would be 2.6 kJ and not 2.6 kJ/mol. (It's 1.3 kJ/mol and you have 2 mols of it).
Your calculations are correct. Here are the Delta G values for each reaction using the given Delta Gf values:
a) Delta G = 2.6 kJ/mol
b) Delta G = -49.3 kJ/mol
c) Delta G = -92.2 kJ/mol
You're welcome!
Yes, your calculations and answers are correct. To calculate ΔG for each reaction using ΔGf values, you need to use the following formula:
ΔG = Σ(ΔGf products) - Σ(ΔGf reactants)
Here's the breakdown of each calculation:
a) H2(g) + I2(s) ---> 2HI(g)
ΔG HI = +1.3 kJ/mol (from table)
ΔG H2 = 0 (by definition)
ΔG I2 = 0 (by definition)
ΔG = (2 * 1.3) kJ/mol = 2.6 kJ/mol
b) MnO2(s) + 2CO(g) ---> Mn(s) + 2CO2(g)
ΔG MnO2 = -465.2 kJ/mol (from table)
ΔG CO = -137.16 kJ/mol (from table)
ΔG CO2 = -394.39 kJ/mol (from table)
ΔG Mn = 0 (by definition)
ΔG = (1 * 0) + (2 * -394.39) - ((-465.2) + (2 * -137.16)) = -49.3 kJ/mol
c) NH4Cl(s) ---> NH3(g) + HCl(g)
ΔG HCl = -95.30 kJ/mol (from table)
ΔG NH3 = -16.4 kJ/mol (from table)
ΔG NH4Cl = -203.89 kJ/mol (from table)
ΔG = (-203.89) - ((-16.4) + (-95.30)) = -92.2 kJ/mol
Therefore, the values you provided are correct:
a) ΔG = 2.6 kJ/mol
b) ΔG = -49.3 kJ/mol
c) ΔG = -92.2 kJ/mol
You're welcome!