The pH the a solution explains its acidity and also is the an unfavorable logarithm (log) of its hydrogen ion concentration. The hatchet pH is used since the hydrogen ion concentration in services of weak acids and in countless other fluids is commonly much less than 1. Therefore, when the concentration is to express exponentially, it contains a an unfavorable exponent. Many people find numbers with an adverse exponents to be confusing, and also they answer with some suspicion such questions as: Is 1.8 X 10-4 larger or smaller sized than 3.6 X 10-5? (To prize the question, state both numbers v the same exponent the 10. This restatement transforms 3.6 X 10-5 to 0.36 X 10-4, a worth that is plainly less than 1.8 X 10-4.) To protect against confusion once dealing with little numbers, dissociation constants and ion concentration are declared not in exponential form, but as the an unfavorable logarithms the the yes, really values. The letter p has been liked to typical "negative logarithm of." Thus, pH method the an unfavorable log the the hydrogen ion concentration, and also pOH method the an adverse log that the hydroxide ion concentration:

pH = -log pOH = -log

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A. Calculate of pH On many hand-held calculators we can calculate pH with the press of a button. To calculate the pH of a solution with a hydrogen ion concentration of 0.0003 M, get in .003 on your calculator. Find and press the Log button to uncover the log of 0.003. The number now on the screen of your calculator is - 2.52.

log(3.0 X 10-3) = - 2.52

To uncover the an adverse of - 2.52, press the +/- switch on her calculator. The number ~ above the display of your calculator is 2.52.

- ( - 2.52) = 2.52

The pH is the an adverse log the the hydrogen ion concentration; thus, because that = 3.0 X 10-3, pH = 2.52.

Example:

a. Calculate the pH that a systems with a hydrogen ion concentration that 0.00040 M.

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b. Calculation the hydrogen ion concnetration that a equipment of pH 8.52.

Solution

a. State in exponential form:

= 0.00040 M = 4.0x10-4 M

Determine the log in of making use of Table 12.6 or your calculator:

pH = -log(4.0x10-4) = -(log 4.0 + log in 10-4)

= -<0.602 +(-4)> = -0.602 + 4 = 3.40

b. This calculation is carry out by reversing the steps in component a.

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pH = -log = 8.52 = 9 - 0.48

log = -9 + 0.48

= (antilog 0.48)x10-9 M

= 3.0x10-9 M

B. The translate of pH Values when the hydrogen ion concentration is proclaimed in exponential notation, the smaller the exponent, the greater the acidity of the solution. Consequently, with pH values, the lower the pH, the more acidic the solution.In 0.1 M HCl = 1 X 10-1 MpH = 1In 0.0001 M HCl = 1 X 10-4 MpH = 4 number 12.2 reflects the pH that several familiar fluids. Many of these values space the midpoint the a range. Human being blood plasma usually varies only in between pH 7.35 and also pH 7.45. Human being gastric fluid is much an ext acidic; the normal range is between pH 1.0 and pH 2.0.
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number 12.2 pH and hydrogen ion concentration.