MF17083:For the following reaction find Kp at 25°C and indicate whether Kp should increase or decrease as the temperature rises. NH4HS(s) <===> H2S(g) + NH3(g); DH° = 83.47 kJ and DG° = 17.5 kJ at 25°C.
- A. B. C. D. E. F. Kp =
- A. B. C. D. E. F. Kp ________ as the temperature rises.
Choices:
A. 0.00086
B. 1200
C. 0.0012
D. increases
E. decreases
F. remains the same
I believe is Kp=0.0012 and Kp increases as the temperature rises can somebody verify that I am correct.
I found 8.6 x 10^-4 for Kp. I used
delta Go = -RT ln K.
delta Ho indicates the reaction is endothermic; therefore, an increase in T will move the reaction to the right, increaseing both pNH3 and pH2S so Kp will increase.
Check my thinking.
if a chemical has the pH of 2 what would be the [H
+]
pH = - log(H^+)
2=-log(H^+).
(H^+)= ??
H^+ = 10^-2
To find Kp at 25°C for the given reaction NH4HS(s) <===> H2S(g) + NH3(g), and determine whether Kp should increase or decrease as the temperature rises, we can follow these steps:
1. Use the equation ΔG° = -RT ln K to find Kp at 25°C, where ΔG° is the standard Gibbs free energy change, R is the gas constant (8.314 J/mol·K), T is the temperature in Kelvin, and K is the equilibrium constant.
2. Substitute the given values into the equation:
ΔG° = 17.5 kJ (convert to J by multiplying by 1000)
T = 25°C = (25 + 273) K
3. Solve for Kp:
Kp = e^(-ΔG° / (RT))
4. Calculate Kp by plugging in the values:
Kp = e^(-17500 J / (8.314 J/mol·K * 298 K))
Using this calculation, we find Kp = 0.0012 (approximately).
Now, let's determine how Kp changes as the temperature rises:
1. Given that ΔH° = 83.47 kJ, which indicates the reaction is endothermic. An increase in temperature will favor the forward reaction to consume heat, therefore shifting the equilibrium to the right.
2. When the equilibrium shifts to the right, the concentrations of H2S and NH3 (products) will increase, while the concentration of NH4HS (reactant) will decrease.
3. Since Kp is directly proportional to the concentrations of the products and inversely proportional to the concentration of the reactant, an increase in the concentrations of the products will lead to an increase in Kp.
Therefore, as the temperature rises, Kp will increase.
So, your answer that Kp = 0.0012 and Kp increases as the temperature rises is correct.
To find the value of [H+], we can rearrange the equation for pH:
[H+] = 10^(-pH)
In this case, pH is given as 2:
[H+] = 10^(-2)
Taking the negative power of 10, we have:
[H+] = 0.01