calculate the standard free-energy change for the synthesis of hydrazine from nitrogen and hydrogen.
N2(g) + H2(g) right arrow N2H4(l)
N2 + 2H2 ==> N2H4
dGrxn = (n*dGf products) - (n*dGf reactants).
According to my tables N2H4 is -16 kJ/mol, N2 and H2 are zero.
You need to use the numbers in your tables.
To calculate the standard free-energy change (ΔG°) for the synthesis of hydrazine from nitrogen and hydrogen, you need to use the standard Gibbs free energy of formation (ΔG°f) values.
The standard free-energy change can be calculated using the equation:
ΔG° = ∑nΔG°f(products) - ∑nΔG°f(reactants)
Where ∑nΔG°f(products) is the sum of the standard free-energy change of formation for each product, and ∑nΔG°f(reactants) is the sum of the standard free-energy change of formation for each reactant.
First, you need to determine the ΔG°f values for each species involved in the reaction. You can find these values in tables or databases of thermodynamic data.
Using the given reaction:
N2(g) + H2(g) → N2H4(l)
Here are the ΔG°f values for each species:
ΔG°f(N2(g)) = 0 (since it is in its standard state)
ΔG°f(H2(g)) = 0 (since it is in its standard state)
ΔG°f(N2H4(l)) = 50.6 kJ/mol
Now substitute these values into the equation to solve for ΔG°:
ΔG° = (1 × ΔG°f(N2H4(l))) - (1 × ΔG°f(N2(g))) - (1 × ΔG°f(H2(g)))
ΔG° = (1 × 50.6 kJ/mol) - (1 × 0 kJ/mol) - (1 × 0 kJ/mol)
ΔG° = 50.6 kJ/mol
Therefore, the standard free-energy change for the synthesis of hydrazine from nitrogen and hydrogen is 50.6 kJ/mol.