AP Biology discussion notes

Wednesday 8/27

Goals for Today:

1. Be able to describe and apply basic chemistry concepts

2. Be able to understand and calculate the pH of different solutions

Question of the Day:What gives water its “magic”?

Hydrogen Bonds

OH H

OH H

H2O

H2O

Hydrogen Bonds

OH H

OH H

Once in a rare, but predictable while a hydrogen from one water molecule will be pulled to the other water molecule as the hydrogen bond pulls apart creating….

Hydrogen Bonds

The creation of these ions, while relatively rare, is important because they are very reactive molecules. This reaction IS reversible, and these ions can (and do) combine to reform 2 water molecules

Hydrogen BondsThis reaction leads us to pHantastically pHun pH!

pH – What does it stand for?

Hydrogen BondsThis reaction leads us to pHantastically pHun pH!

pH – the Power (or Potential) or Hydrogen

pH – the POWER of Hydrogen (or hydronium)In pure water this odd reaction happens about 1 in every 10,000,000 molecules!

pH – the POWER of Hydrogen (or hydronium)pH is measured on a log scale

This means that each level is 10X different than the level before.

The pHantastically, pHun pH Scale

pH – the POWER of Hydrogen (or hydronium)pH is measured on a log scaleLogistically speaking then a pH of 1 is 10X more acidic than a pH of 2. A pH of 1 is 1000 times more acidic than a pH of 3 (10 x 10 x 10 or 103)-> NOT 30x more powerful!

Know these formulas!!Formula for pH:

pH = -log [ H+]

pOH= -log [ OH]

pH + pOH = 14

Calculating pHFormula for pH:

pH = -log [ H+]pH = -log[ 1/10,000,000]pH = 7

pH and living things

Living things have relatively stable internal pH, that can vary throughout the body.

What human body part do you know that is at a lower pH than the rest of your body?

pH and living things

Buffer – any substance that minimizes OH- and H+ concentrations

Buffers are extremely important in stabilizing the pH of organisms and are chemicals that are able to donate H+ ions when there are too few and accept H+ ions when there are too many.

pH and living thingsWhat problems are you aware of that humans might contribute to in terms of changes in the pH of the natural environment?

Extra Credit Opportunity!

-Research Ocean Acidification AND Acid Rain. Describe both the chemistry behind each and the impact on organisms (living things) in the environment. ( This information CAN be found in your book!!)- through Friday 8/29

Species of the Day 8/27

Northern Cardinal: Cardinalis cardinalis

Species of the Day 8/27Northern Cardinal: Cardinalis cardinalis

Species of the Day 8/27Northern Cardinal: Cardinalis cardinalis

Species of the Day 8/27

Northern Cardinal: Cardinalis cardinalisIF the pH in the stomach of this Cardinal had a Hydrogen Ion concentration of [H+] = 1.78 x 10-4 what would the pH of it’s stomach be?

What formula would we use (write this out too…in other words show your work!)?