Acids and Bases n.gif

Why are they important? They are found on the Earth you walk, the foods you eat and the products that you, not to mention who important your amino acids are These two flowers are the same species. Why are the different colors? Their color depends on the acidity of the soil that they are grown in

Taste

The pH Scale The measurement of H+ (acid) pOH = measure of OH-(base) ions. Lots of H+ = Acid Lots of OH- = Base

pH + pOH = 14 What is the pH of a solution that has a pOH of 9? –Substute in pH+9= 14 pH = 5

Think you’ve got it?

The Basic Formula Acid + Base  Salt+ Water HA +BOH  BA + H 2 O What is a salt again? –General way to describe an ionic bond Acid and base reactions can happen forward and backwards

Acids contain H+ (proton) Sour in taste Strong Vs. Weak –Strong = pH 1-4 (molecule will break apart) –Weak = pH 3-6 ( only some molecule will) Example: –HCl  H + +Cl-

Bases Contain OH- Alkaline Strong Vs. Weak –Strong = pH –Weak = pH 8-10 (only some break apart)

Neutral pH = 7 Neutraization –When acids and bases are mixed Antacid –Stomach acid + antacid = neutralized stomach –Let’s visit The Alien Juice Bar

BAAD Acronym Bases Accept protons (H+) Acids Donate protons(H+)

Progress Check

Solution stoichiometry Concentration [ } = concentration in moles/ liter pH = -log [H+] pH scale Reactions with solution Neutralization reaction

10.0 ml of 1.5 M HCl solution neutralizes a 30.0 ml sample Ca(OH) 2. What is the concentration (M) of the Ca(OH) 2 solution? First step = Balance the Equation 2 HCl + Ca(OH) 2  CaCl 2 + 2H 2 O Next start w/ given and follow units until unknown.01 L x 1.5 M HCl x 1 moles Ca(OH) 2 1 L2 moles HCl =.0075M Ca(OH) 2 *.0075 M Ca(OH) 2 =.25M.03L

15.9 ml of 2.50M Al(OH) 3 solution is used to neutralized a 25.0 ml sample of H 2 SO 4. Calculate the molarity of H 2 SO 4 Solution. First, balance the equation 2Al(OH) 3 + 3H 2 SO 4  Al 2 (SO 4 ) 3 + 6H 2 O Next, start w/ given and follow units until unknown.159L x 2.50moles Al(OH) 2 x 3 moles H 2 SO 4 1L 2moles Al(OH) 2 =.6M H 2 SO 4.6 M H 2 SO 4 = 24M.025L

Indicates pH Change colors at different pH Levels Types –Universal –Phenolphthalein Clear  Pink  Magenta * For our lab we went to stop at pink Indicators

Cabbage Indicator

pH calculations pH = measure of H

Buffers Resist change to pH Example –Holding your breath will build up the concentration of CO2 in your body. –That changes the pH in your blood –Exhaling the CO2 changes the pH back to normal