Question

gastric juice (ph 1.5) is produced by pumping HCl from blood plasma (ph 7.4) into the stomach. Calculate the amount of free energy required to concentrate the H in 1 L of gastric juice at 37 degrees celsius

Answer 1

Answer:

∆G = 35 KJ

Explanation:

The given data are as follows;

Gastric juice pH = 1.5

Blood plasma pH = 7.4

Temperature = (37 + 273) K = 310 K

However, pH = -log [H+]

Therefore, [H+] = 10^-pH

At pH of 1.5, [H+] = 10^-1.5 = 3.16 × 10^-2 M

At pH of 7.4, [H+] = 10^-7.4 = 3.98 × 10^-8 M

Using ∆G = RTln(C2/C1)

Where R = 8.314 J/mol/K;

T = 310 K;

C2 (concentration inside) = 3.16 × 10^-2 M;

C1 (concentration outside) = 3.98 × 10^-8 M

∆G = 8.314 × 310 × ln(3.16 × 10^-2 / 3.98 × 10^-8)

∆G = 35012.74

Therefore, ∆G = 35 KJ