Question

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)

Answer 1

The Delta G values for the given reactions are: a) -33.4 kJ/mol, b) -787.9 kJ/mol, c) -354.8 kJ/mol.

Step-by-step explanation:

Calculate the Delta G for the reaction H2(g) + I2(s) -> 2HI(g) using the Delta Gf values for each compound. The Delta Gf values are: Delta Gf (H2) = 0 kJ/mol, Delta Gf (I2) = 0 kJ/mol, Delta Gf (HI) = -16.7 kJ/mol. Delta G = (2 * Delta Gf (HI)) - (Delta Gf (H2) + Delta Gf (I2)) = (2 * -16.7 kJ/mol) - (0 kJ/mol + 0 kJ/mol) = -33.4 kJ/mol. Therefore, the Delta G for this reaction is -33.4 kJ/mol.

1. Calculate the Delta G for the reaction MnO2(s) + 2CO(g) -> Mn(s) + 2CO2(g) using the Delta Gf values for each compound. The Delta Gf values are: Delta Gf (MnO2) = -526.4 kJ/mol, Delta Gf (Mn) = 0 kJ/mol, Delta Gf (CO) = -110.5 kJ/mol, Delta Gf (CO2) = -393.5 kJ/mol. Delta G = (Delta Gf (Mn) + 2 * Delta Gf (CO2)) - (Delta Gf (MnO2) + 2 * Delta Gf (CO)) = (0 kJ/mol + 2 * -393.5 kJ/mol) - (-526.4 kJ/mol + 2 * -110.5 kJ/mol) = -787.9 kJ/mol. Therefore, the Delta G for this reaction is -787.9 kJ/mol.
2. Calculate the Delta G for the reaction NH4Cl(s) -> NH3(g) + HCl(g) using the Delta Gf values for each compound. The Delta Gf values are: Delta Gf (NH4Cl) = -314.6 kJ/mol, Delta Gf (NH3) = -46.1 kJ/mol, Delta Gf (HCl) = -92.3 kJ/mol. Delta G = (Delta Gf (NH3) + Delta Gf (HCl)) - Delta Gf (NH4Cl) = (-46.1 kJ/mol + -92.3 kJ/mol) - (-314.6 kJ/mol) = -354.8 kJ/mol. Therefore, the Delta G for this reaction is -354.8 kJ/mol.