Determine the ph of a 0.62 m nh4no3 solution at 25°c. The kb for nh3 is 1.76 × 10-5.

ph = 4.73

Explanation:

Determine the pH of a 0.62 M NH4NO3 solution at 25C

The Kb for NH3 is 1.76 x 10^-5

NH4+ is the conjugate acid of the base NH3

Ka for NH4+ = K water / K NH3 conjugate base

Ka = 1 × 10⁻¹⁴ / 1.76 10⁻⁵

     = 5.68 × 10⁻¹⁰

which is he Ka for

NH4 + H2O --> NH4OH + H⁺

Ka = [NH4OH] [H+] / [NH4)+]

5.68 × 10⁻¹⁰ = [X] [X] / [0.62]

X² = 3.52 × 10⁻¹⁰

X = [H+] = 1.88   × 10⁻⁵

p of that H+ = 4.73

ph = 4.73

the formula mass of a molecule or a compound is the sum of the atomic weights of the atoms in its empirical formula

(that's what i know about formula mass)