What goes up- Always comes down!

Stunt Mouse

Acids and Bases Lesson 5

pH stands for power of Hydrogen

HF – Hydrofluoric Acid Is so strong it can eat through the skin and start oxidizing the calcium in the bone.

pH of common things

Acid and Bases

NaOH change in pH

Finding the [H + ] from pH Find the [H + ] if the pH is First enter the number 8.79 and make it (-). Then hit the 2 nd button and then log. Find the [H + ] if the pH is First enter the number 8.79 and make it (-). Then hit the 2 nd button and then log.

Answer 1.62 x M

Find the [OH - ] from pH Find the [OH-] if the pH is Take the number and subtract it from 14 and then take the negative value. ( ) then hit the 2 nd button and log. Find the [OH-] if the pH is Take the number and subtract it from 14 and then take the negative value. ( ) then hit the 2 nd button and log.

Answer 5.89 x M

Spectator ions Are ions not actually involved in the reaction.

Ionic equation Instead of writing an overall equation, by writing the solutions involved as ions in solution, show which ions break apart and how they reassemble.

Net Ionic Equation Represents the reaction after all common ions to both sides have been removed.

Problem 1 Write the overall and ionic equations for the following reaction. Hydrochloric acid reacts with sodium hydroxide to produce water and aqueous sodium chloride. Write the overall and ionic equations for the following reaction. Hydrochloric acid reacts with sodium hydroxide to produce water and aqueous sodium chloride.

Work Overall Equation: HCl (aq) + NaOH (aq) > H 2 O (l) + NaCl (aq) Check is it balanced, if yes proceed. Overall Equation: HCl (aq) + NaOH (aq) > H 2 O (l) + NaCl (aq) Check is it balanced, if yes proceed.

Work Cont Ionic Equation: Break apart all compounds except those that are solid (s), liquid (l), or gas (g). H + (aq) + Cl - (aq) + Na + (aq) + OH - (aq) ----> H 2 O (l) + Na + (aq) + Cl - (aq) Ionic Equation: Break apart all compounds except those that are solid (s), liquid (l), or gas (g). H + (aq) + Cl - (aq) + Na + (aq) + OH - (aq) ----> H 2 O (l) + Na + (aq) + Cl - (aq)

Work Cont. Net Ionic Equation: Cancel the ions on both the left and right side of the equation that are in common. Write the remaining substances. Net Ionic Equation: Cancel the ions on both the left and right side of the equation that are in common. Write the remaining substances.

Net Ionic Equation H + (aq) + OH - (aq)  H 2 O (l)

Neutralization

Problem 2 Find the OH - if the [H + ] is 7.3 x M. Remember K w = [H + ] x [OH - ] 1x M 2 = 7.3 x M x [OH - ] Answer 1.37 x M Find the OH - if the [H + ] is 7.3 x M. Remember K w = [H + ] x [OH - ] 1x M 2 = 7.3 x M x [OH - ] Answer 1.37 x M

Problem 3 Find the pH if the [H + ] is 1.91 x M. Remember pH = - log of [H + ] (-)Log of 1.91 x M Answer Find the pH if the [H + ] is 1.91 x M. Remember pH = - log of [H + ] (-)Log of 1.91 x M Answer 11.72

Problem 4 Find the pH if the [OH - ] is 7.18 x M. Remember pH = - log of [H + ], but you have the [OH - ]. Find the [H + ] first. Find the pH if the [OH - ] is 7.18 x M. Remember pH = - log of [H + ], but you have the [OH - ]. Find the [H + ] first.

Work 1 x M 2 = 7.18 x M x [H + ] [H + ] = 1.39 x M Take the –log of 1.39 x Answer = x M 2 = 7.18 x M x [H + ] [H + ] = 1.39 x M Take the –log of 1.39 x Answer = 6.86

CuSO 4 with NH 3