Acids and Bases

Vocab Acid…produces H+ ions in water Base…produces OH- ions in water Buffer…a substance added to minimize the affects on pH Hydronium ion…H30+ Indicator…changes color in acids/bases

Neutralization…chemical reaction that takes place between an acid and base in water pH…measure of H+ concentration Salt…formed with the + ion from the base and - ion of the acid Soap…organic salts

Strong acid…ionizes almost completely in water Strong base… acid…ionizes almost completely in water Titration…used to determine the concentration of an unknown Weak acid… does not ionize completely in water Weak base…does not ionize completely in water

HCl + H2O  H3O+ + Cl– Acids Definition of an acid Ionize to form hydronium ions (H3O+) in water HCl + H2O  H3O+ + Cl–

Acids All acids have at least one hydrogen that can be removed when added to water. The hydrogen ions, H+, react with water to form hydronium ions, H3O+ Can burn tissue. React with indicator paper to produce a predictable color change. Ex. Litmus turns red in acid.

Properties ACIDS BASES sour taste corrosive electrolytes turn litmus red react with metals to form H2 gas bitter taste corrosive electrolytes turn litmus blue slippery feel

ACIDS Common acids: Citric acid Lactic acid Acetic acid Examples: H3PO4 - soft drinks, fertilizer, detergents H2SO4 - fertilizer, car batteries HCl - gastric juice HC2H3O2 - vinegar Common acids: Citric acid Lactic acid Acetic acid Hydrochloric acid

Bases NH3 + H2O  NH4+ + OH- Definition of a Base Dissociate or ionize to form hydroxide ions (OH-) in water NH3 + H2O  NH4+ + OH-

BASES Examples: NaOH - lye, drain and oven cleaner Mg(OH)2 - laxative, antacid Common bases: Ammonia Milk of magnesia Baking soda Soap

Form hydroxide ions, OH-, in water. Accepts hydrogen ions from acids. Bases Form hydroxide ions, OH-, in water. Accepts hydrogen ions from acids. Turn litmus paper blue.

Acids and Bases Acids produce H+ in aqueous solutions water HCl H+(aq) + Cl- (aq) Bases produce OH- in aqueous solutions NaOH Na+(aq) + OH- (aq)

Strength of Acids and Bases The ability of an acid or base to ionize in solution affects its strength. An acid that ionizes almost completely is a strong acid. H2SO4 and HCl are examples. An acid that only partially ionizes is a weak acid such as carbonic or acetic.

Concentrated vs Dilute You can have dilute solutions of strong or weak acids and bases. This is not weak or strong!

The measure of hydrogen ion concentration What is the pH scale? The measure of hydrogen ion concentration The more H ion, the greater the acidity.

What is the pH scale? The pH scale measures how acidic or basic a solution is.

Identifying Acids and Bases Acids have a ph from 0-7 Lower pH value indicates a stronger acid. Bases have a pH from 7-14 Higher pH value indicates a stronger base. **Acids and bases react together in a NEUTRALIZATION reaction

A pH level of 7 indicates a Neutral Substance aka WATER! Neutral pH A pH level of 7 indicates a Neutral Substance aka WATER!

Working with Indicators Red litmus turns BLUE in the presence of Bases Blue litmus turns RED in the presence of acid Acids and bases react together in a NEUTRALIZATION reaction Lesson 5/6 Demo frothing rainbow (KISS)?????????????????? Draw on board word equation Reactants -- Products, Acid + base --- salt + water eg HCl + NaOH - NaCl + H2O ALWAYS OBSERVE WHEN MIXING CHEMICALS SMELL< FIZZ< HEAT< COLOUR ETC EXPT H/O indicators worksheet work in groups (make own indicator) EXPT find Ph of everyday substances H/O WRITE UP CORRECTLY, conclusion BLUE ALKALI, RED ACID< GREEN NEUTRAL

Titration standard solution unknown solution Titration Process in which a standard solution is used to determine the concentration of an unknown solution.