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Unformatted text preview: After taking the smallest amount to zero, if H + or OH-is left over, just take the log and get the pH. PROBLEM TYPE II Double arrows means an equilibrium problem and Xs will be in the rice chart. Example: 0.1 mole of HF and 0.5 mole of NaF are mixed to make one liter. R HF + H 2 O H 3 O + + F-I 0.1 0 0.5 ( ignore the water because it will not be in the K expression) C -X X X E 0.1 - X X 0.5 + X Now substitute the E column into the equilibrium expression and solve for X. Since the Ka for HF is so small ( 7.2 X 10-4 ) the X compared to 0.1 and 0.5 may be ignored so the quadratic equation does not have to be used....
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- Spring '08