The delta G^o for a reaction :
h2 (g) + i2 (g) = 2HI(g)
Is 2.6 kj/moles. In one experiment the initial pressures are P h2 = 4.26 atm, P i2 = 0.024 atm, P hi = 0.23 atm. Calculate delta G
Use dG = dGo + RTlnQ where
Q=(pHI)^2/pH2*pI2
To calculate ΔG (Gibbs free energy change) for the reaction, you need to use the following formula:
ΔG = ΔG° + RT * ln(Q)
Where:
- ΔG° is the standard Gibbs free energy change (given as 2.6 kJ/mol)
- R is the gas constant (8.314 J/(mol·K))
- T is the temperature in Kelvin
- Q is the reaction quotient
First, convert the given pressure values to concentrations using the ideal gas law:
P(H2) = 4.26 atm
P(I2) = 0.024 atm
P(HI) = 0.23 atm
Since the reaction is in gas phase, we can assume that the total volume remains constant. Therefore, we can write:
PV = nRT
Using this equation, we can calculate the number of moles of each gas:
n(H2) = (P(H2) * V) / RT
n(I2) = (P(I2) * V) / RT
n(HI) = (P(HI) * V) / RT
The volume cancels out when calculating the reaction quotient Q:
Q = (P(HI)^2) / (P(H2) * P(I2))
Substitute the pressure values into the equation to calculate Q:
Q = (0.23^2) / (4.26 * 0.024)
Now, substitute the values into the equation ΔG = ΔG° + RT * ln(Q):
ΔG = 2.6 kJ/mol + (8.314 J/(mol·K) * T) * ln(Q)
For example, if T = 298 K:
ΔG = 2.6 kJ/mol + (8.314 J/(mol·K) * 298 K) * ln(Q)
You can calculate ΔG by substituting the appropriate values for T and Q into the equation.
To calculate delta G (Gibbs free energy) for a reaction using the given information, we need to use the equation:
delta G = delta G^o + RT * ln(Q)
where:
- delta G is the Gibbs free energy change of the reaction.
- delta G^o is the standard Gibbs free energy change of the reaction, given as 2.6 kJ/mol.
- R is the ideal gas constant, which is approximately 8.314 J/(mol·K).
- T is the temperature in Kelvin.
- Q is the reaction quotient, which can be calculated using the given initial pressures.
First, let's convert the given temperature from Celsius to Kelvin. If the temperature value is not provided, assume a temperature value.
Next, we need to determine the reaction quotient (Q) for the reaction. The reaction quotient is calculated using the following formula:
Q = (P_HI^2) / (P_H2 * P_I2)
where:
- P_HI is the partial pressure of HI.
- P_H2 is the partial pressure of H2.
- P_I2 is the partial pressure of I2.
Using the given initial pressures: P_H2 = 4.26 atm, P_I2 = 0.024 atm, P_HI = 0.23 atm, we can substitute the values into the reaction quotient equation to find Q.
After calculating Q, substitute the values of delta G^o, R, T, and Q into the equation delta G = delta G^o + RT * ln(Q) to find the value of delta G.