Sharp EL-W535TG Operation Manual page 55

Polynomial equation
(This example is for EL-W516T only.)
<Example 2>
Let the acetic acid concentration be c (= 0.1 mol / ), and the hydrogen ion
concentration be x.
(1) Solve the following quadratic equation to find the hydrogen ion concentration x:
x
where
K
a
K
w
(2) Use the result of (1) to find the pH (= - log x) of acetic acid.
pH = - log x (x>0)
(1)
Save constants
2.75
1.0
0.1
3 + K x 2 - (cK + K
a a w
-5
= 2.75 x 10 [mol / ] (ionization equilibrium constant of acetic acid)
-14
= 1.0 x 10 [mol / ] (ionic product of water)
Operation
(NORMAL)
5
14
C
)x - K K = 0
a w
B
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