CHM135H1 Lecture Notes - Lecture 19: Nitric Acid, Ph, Hydronium
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CHM135H1 Full Course Notes
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Water can be and acid or a base. Kw = [h30 +][oh -] = 10^-14. Higher hydronium c -> lower hydroxide c. At 25 , chemist has solution with [h3o +] = 3x10^ -4 m. what is [oh-]? wkw / [h30 +] = [oh-] Ka is an indication of acid strength. Kb is an indication of base strength. Hno3 + h20 -> no3 - + h30 + (since hno3 is strong acid, it fully dissociates) ph = -log [hydronium] = -log [hno3] = -log (0. 025) = 1. 6 ph. Calculate ph and poh for 0. 3m hno3 ph = 0. 52 (-log(0. 3)) poh = 13. 42 (14 - 0. 52) Assumption : concentration of ha does not change. Finding ka of weak acid from ph ph of 0. 12m hpac = 2. 62. [h30] = 10 ^ - ph = 0. 0024 = x. Ka = x^2 / 0. 1 x = 0. 00011m. Then check, x/0. 1 * 100, if <5%, assumption is fine.
