1. Lesson 4

1.5. Explore 4

Mathematics 30-2 Module 7

Module 7: Exponents and Logarithms

 

 

In Lesson 3 you worked with the pH formula to find the hydrogen ion concentration and the pH value. In Try This 4 you will use a graph of the pH and hydrogen ion concentration to solve problems.

 

Try This 4

 

The following two graphs show the relationship pH = −log x, where x is the hydrogen ion concentration of a solution. The two graphs show the same function, but with different x-axis scales.

 

This is a graph of the function pH = –log x. It starts in quadrant I and ends in quadrant IV. The x-intercept is one comma zero. The x-axis goes from 0 to 1.2.
 
 
This is a graph of the function pH = –log x. It starts in quadrant I at high positive y values, and decreases as x increases. The x-axis goes from 0 to 0.00012.

 

 


  1. This picture shows pH indicator paper in a blue liquid.

    iStockphoto/Thinkstock

    Use the graphs to determine the pH when the hydrogen ion concentration is
    1. 0.4
    2. 0.000 04
  2.  
    1. For what hydrogen ion concentrations is each graph useful?
    2. For what pH range is each graph useful?
  3.  
    1. Describe an advantage and a disadvantage to using a graph to represent a logarithmic function such as the pH graphs shown.
    2. Describe an advantage and a disadvantage to using an equation such as pH = −log x to represent a logarithmic function.

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