LESSON 2
DETERMINING pH AND SPECIFIC GRAVITY
OBJECTIVE:
In this lesson you will learn how to utilize the pH meter to determine the acidity and alkalinity
of a photographic developer and fixer, and you will use a hydrometer to measure the specific gravity of a
photographic developer and fixer.
Upon completion of this lesson you will be able to:
1.
Identify whether two or more solutions are acid or alkaline, given their pH readings.
2.
Identify whether two or more solutions are lighter or heavier than distilled water, given
their specific gravity readings.
3.
List the steps used to operate a Beckman pH meter.
CREDIT HOURS...................................................................
Hours
MATERIAL REQUIRED......................................................None
SECTION I
2-1.
pH METER. "pH" can be defined as the measurement of the acidity or alkalinity of a solution.
The instrument used to measure pH is called a pH meter.
NOTE:
THERE ARE ALSO TWO CHEMICALLY INPREGNATED INDICATOR PAPERS
USED TO READ THE pH OF SOLUTIONS. ONE IS CALLED LITMUS PAPER;
THE OTHER PHYDRION. WHEN IMMERSED IN A SOLUTION THESE
PAPERS WILL CHANGE COLOR. THEIR PARTICULAR CHANGE IN COLOR
IS COMPARED TO A COLOR SCALE TO DETERMINE THE APPROXIMATE
pH. FOR THIS LESSON, HOWEVER, CONCERN YOURSELF ONLY WITH THE
pH METER.
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