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Untitled.notebook
December 14, 2016
8.7 Logarthmic Scales
1. Earthquakes
intensity of any earthquake with magnitude
instead of calculating the intensity we COMPARE the intensities
and magnitudes
Ex An earthquake of magnitude 7.5 on the Richter scale struck Guatemala
on Feb 4, 1976 killing 23 000 people. On October 2, 1993 an earthquake of
magnitude 6.4 killed 20 000 in Maharashtra India. Compare their intensities.
Let I be the intensity of the earthquake in India
Then I is the intensity in Guatemala
the Guatemala earthquake was approx 12.6 x as strong as
the earthquake in India
Calculate the magnitude of an earthquake that is twice as intense as the
San Francisco earthquake of 1989, which had a magnitude of 6.9
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Untitled.notebook
December 14, 2016
Sound
How many times more intense is a rock concert than a normal
conversation
Chemistry
chemists measure the acidity or alkalinity of a liquid by determining
the concentration of H+ ions in the liquid.
This is a very small number pH of 7 is neutral
1 unit decrease from 7 generates a 10 fold increase in acidity
1 unit increase from 7 generates a 10 fold increase in alkalinity
Normal rainwater is slightly acidic pH approx 5.5 because it contains
acids formed by the carbon dioxide it absorbs from the atmosphere
Determine the pH of something that is twice as acidic as normal rainwater.
hydrochloric acid has a hydronium ion concentration of 100 mol/L What
is the pH?
battery acid has a hydronium ion conc of 5 x 10 -9 mol/L
What is the pH?
soft drinks have a pH of approx 3. What is the concentration of
Hydronium ions?
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