1. 14.5 Common and Natural Logarithms with Applications

2. Remember that the common log is just the logarithm with a base of 10. This section deals a lot with just using your calculator to evaluate the common log with your calculator. Find log7.02 Find log1.39 Find log 9.99

3. Find x if log(x) = 3.8774 Find x if log (x) = 3.9786 Find x if log (x) = -1.5901

4. Magnitude of an earthquake is found using the following formula. M=log (T), where T is the smallest shock that a seismograph can measure.

5. Example The San Francisco earthquake of 1906 is estimated to have measured 8.3 on the Richter scale. The San Fernando earthquake of 1971 measured 6.6 on the Ricther scale. Find T for each earthquake, and then give some indication of how much stronger the 1906 earthquake was than the 1971 earthquake.

6. pH In chemistry, the pH of a solution is the measure of acidity of the solution. The definition of pH involves common logs. H+ is the concentration of Hydrogen Ions in moles per liter. pH is on a scale of 0-14. neutral is 7. acidic is less than 7, basic is above 7.

7. Normal rainwater has a pH of 5.6. What is the concentration of Hydrogen ions in the rainwater?

8. Find the concentration of the hydrogen ions in a can of cola if the pH is 4.1

9. Natural logarithm (LN or ln). This is just a logarithm with the base = e. We will treat it just like any other logarithm. Don’t let the notation of ln confuse you.

10. Use properties to expand/condense