WRITE YOUR OWN NOTES ON THIS POWERPOINT AND ALL EXAMPLES.

Acids and Bases- 2015

AcidAcid BaseBase

Taste-----sourTouch stingsReacts vigourously

with metalsConductsBlue litmus turns red

Taste-- bitterTouch- slipperyLittle reaction with

metalsConductsRed litmus turns blue

There are 3 definitions of acids and bases. Each definition allows more substances to be classified as an acid or base

Arrhenius Definition

Arrhenius Acid- substance that ionizes to produce H+ ions ex- HCl

Arrhenius Base- substance that dissociates to produce OH- ions ex- NaOH

Problem- must be in a water solution

Lewis Definition

Uses electrons and usually deals with organic chemistry

Bronsted-Lowery Definition

Acid- any substance that donates H+

Base- any substance that accepts H+

This definition allowed Ammonia (NH3) to be classified as a base

Water solution is NOT necessary

Examples

Common Acids and uses

HCl- hydrochloric acid- stomach acid and concrete cleaner

H2SO4- sulfuric acid- dehydrating agent, fertilizers

HNO3- Nitric acid- explosives

H3PO4- Phosphoric Acid- soft drinks

CH3COOH- Acetic Acid- vinegar

Common Bases

NH3 Ammonia- cleanerNaOH- sodium hydroxide-lye soap, drain

cleanerMg(OH)2- Magnesium hydroxide- antacid-

MOMCalcium carbonate- antacid

Bases usually contain OH- (hydroxide) but carbonates and phosphates can form basic salts

NaOH, Ca(OH)2

Salts: CaCO3 Na3PO4

Calcium carbonate is found in chalk, TUMS, sea shells

Organic bases contain the amine functional group (-NH2)

The term alkaline refers to a base solution Example- shampoo commercial advertises that the

shampoo is a slightly alkaline (slightly basic)

Relationship between Acids and Bases

Conjugate Acid –Base pairs: molecules and ions that differ only by one proton (or H+1)

HCN + H2O <--> H3O+1 + CN-1

Acids ionize to form a H+ ionMonoprotic- 1 ionizable H+

Examples: HCl, HF, HBr,

Diprotic Acid- contains 2 hydrogen

H2SO4

Diprotic Acids ionize on H+1 at a time.

Triprotic Acid- contains 3 hydrogens

H3PO4 Phosphoric

Triprotic Acids ionize on H+1 at a time.

A Binary Acid is an acid that contains hydrogen and one other element HBr HCl HF Hydro ______ic

Oxyacid- an acid that contains oxygenH2SO4

HNO3

H3PO4

Carboxylic Acid- An organic acid that will always contain the functional group -COOH Example- Acetic Acid CH3COOH

Strong Acid ionizes completely to produce strong electrolytes

HCl H+ + Cl-

HI and HBr are also strong acids(will discuss diprotic acids later)

Weak Acids ionize incompletely to form weak electrolytes

HF H+ + F-

What property explains why Flourine and hydrogen refuses to break apart completely?

Strong bases- break apart completelyNaOH Na+ + OH-

Remember: Groups 1 and 2 except for Be and Mg

Weak bases break apart incompletely Al(OH)3 Al+3 + OH-

Acid Naming rules

-ate polyatomic forms the –ic acidPer_________ic _________ic _________ousHypo ________ousExamples:

Acid + Base = salt + waterSodium hydroxide + Hydrochloric Acid

Salt: cation comes from the base and the anion from the acid.

Neutralization reaction

Sulfuric Acid + Sodium hydroxide

Carbonic Acid + Aluminum hydroxide

Salts can react in neutralization rx

Hydrochloric Acid + Magnesium carbonate

Phosphoric acid + Calcium carbonate

Sulfuric Acid + Calcium carbonate

Molarity math problems

Salt Prediction

Salt- a compound formed from the reaction of an acid and a base

For each salt predict the acid and base that was used:

Cation –from the base; Anion -from the acidSodium chlorideMagnesium phosphateAluminum nitrate

Net Ionic

Strong Acids and Strong Bases break apartUse this fact along with the solubility rules

from the solutions chapter. Examples:

Quick review

For each salt determine the parent acid and base and strengths for acids

1. Chrominum oxalateGallium sulfide

Write the net ionic reaction for : 2HBr + ZnSO3 ZnBr2 + H2SO3

Buffers

Buffers are acids or bases that are used to prevent the pH from changing.

Bronsted-Lowery definitions for acids and bases explain buffers

How buffers work

Buffers works by absorbing excess H+ or OH- in a solution. This prevents the pH from changing.

Examples:

Antacids work by absorbing excess stomach acid-

They contain a buffer that prevents the stomach’s pH from changing too drastically to a basic pH

Baking soda(homemade antacid) is not buffered. The pH is changed to much and the stomach releases more stomach acid and the indigestion process continues.

Other common uses of buffers

Fish tanks, blood system, swimming pools

Blood system—real life example

Hyperventilation- person breathes too rapidly Too much CO2 is lost pH of the blood increases (too basic)

treatment

Breathe into a bag air is rich with CO2 causes an increase in the H+ and the pH decreases back to normal

Heart Failure

Person fails to release CO2

Too much CO2 in blood systempH of blood becomes too acidic (low pH)

Treatment

IV of sodium bicarbonate(basic salt)Increases the pH back to normal

Amphoteric

A substance the can react as an acid or base depending on the chemical it is reacting with. Examples- Al(OH)3 Water

pH

Water is capable of self ionizing

1.o Liter of water produces 1.0 x 10-7 moles of H3O+ and 1.0 x 10-7 moles of OH-

This allows the Ionization constant for water to be calculated

Calculate the H3O+ and the OH-

1) .00236 M HCl 2) .0000569 M NaOH3) 2.69 x 10-3 M HBr 4) 4.14 x 10-11 M KOH

pH is a way of expressing the hydronium ion concentration

pH scale 7 is neutral less than 7= acid greater than

7= base

Calculate the pH for the following:

1) .000569 M HCl 2) .00489 M HBr

3) 5.69 x 10-5 M HCl

pOH is a way of expressing the hydroxide ion

Calculate the pOH5.69 x 10-6 M NaOH

.00896 M KOH

Determine the 1) hydronium 2) hydroxide3) pH 4) pOH

.00553 M HI

7.23 x 10-4 M LiOH

When given the pH or the pOH the H3O+ and OH- can be calculated: H3O+ = antilog(-pH) or 10-pH

OH- = antilog (-pOH) or 10-pOH

Remember the pH or pOH must be typed in as a negative number

Calculate the hydronium and hydroxide ion concentration for each of the following: 1) pH = 6.43 2) pOH = 3.43

Identify if the substances are acidic ore basic

Calculate the hydronium and hydroxide ion concentration for each of the following:

1) pH = 2.562)pOH = 3.22

Identify if the substances are acidic ore basic

Sample lab problem

How many grams of HCl in a 500 mL solution would be needed to make a solution that has a pH of 2.55? Hint- first calculate the molarity of the hydronium ion.

second- calculate the number of grams required to make this Molarity solution. (don’t worry- we are smushing the material)

Answer:

Sample Lab Problem

The lab needs a 250 mL solution of .666 M Sodium hydroxide. The only sodium hydroxide available is 5.00 M. How many mL of the 5.00 M solution is needed? (dilution problem from Molarity test)

Sample Lab Problem

What is the pH of the 5.00 M solution of NaOH and what is the pH of the .666 M solution of NaOH?

Sample Lab Problem

How many grams of Sodium hydroxide would be needed to make 500. mL of a 5.00 M solution?

JUST SMUSHING

On the lab sheet- you will have to calculate the hydronium ion, hydroxide ion, pH, pOH and combine these concepts with the Molarity chapter.

NO molality on the lab

If the pH of sodium hydroxide is 11.6, what is the pOH?

Calculate the pH of a bottle of sodium hydroxide that has a .0564 M.

Calculate the pH of a bottle of HBr that has a .000985 M.

If the pH of a solution is 5.67 Calculate the OH-, H3O+ for the solution. Show the formulas that you used.