MathBench > Measurement

Logs and pH

Differences in acidity

Remember how we calculated the difference in energy released by two earthquakes? You can do the same thing with acidity:

The pH of lemon juice is 4.2. The pH of milk is 7.8. What is the difference in hydrogen ion concentration (approximately)?

lemons

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I think I have the answer: 3981 times as much.

 

Finally, can you figure out how to use the "unlogging" trick to calculate the concentration?

The pH of lemon juice is 4.2. How many moles of H+ are present in 5 litres of lemon juice?

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I think I have the answer: 5 * 10−4.2 = 0.000315 moles of H+