Answer:
Decreases
Explanation:
The atmospheric pressure on the surface of the mercury pushes it up the evacuated tube until the downward pressure of the mercury equals the atmospheric pressure.
If the atmospheric pressure decreases, the mercury doesn't have to rise as high.
The mercury height decreases.
Answer:
The answer to the question is;
The equilibrium constant,K, at 25 °C for the reaction between Ni²⁺(aq) and Zn(s), which form Ni(s) and Zn²⁺ is 2.04×10¹⁷.
Explanation:
The half reactions are as follows
Ni²⁺ (aq) + 2e⁻ -> Ni (s)
Zn (s) -> Zn²⁺ (aq) + 2e⁻
For the Ni²⁺/Ni system we have the potential given as -0.23V (Reduction)
For the Zn²⁺/Zn sytem, the potential is -0.76. Here however, we should note that the zinc is being oxidized and therefore the potential is positive, that is;
Zn/Zn²⁺ = 0.76
Therefore the voltage for the sum of the reactions on both sides of the process is
-0.23 V + 0.76 V = 0.53 V
We then call upon the Nernst equation to calculate the equilibrium constant as follows
E⁰ =
Where:
E⁰ = Standard cell potential = 0.53 V
n = Number of moles of electrons = 2 moles of e⁻
K = Equilibrium constant
Therefore we have
0.53 V =
Therefore log K = 17.905
and K = = 2.04×10¹⁷.