2 Calculate the concentration or volume of an acid or base from the concentration and volume of an acid or base required for neutralization.Using a standardized acid or base, determine the concentration of an unknown base or acid.Additional KEY Termsstandard solution equivalence pointend point titration
3 HA + BOH BA + H2O Titration – quantitative chemical reaction. unknown reacted with a standard solutionused to find [ ] of unknown solutionStandard solution – solution of known concentration which is compared to unknown.HA + BOH BA + H2O2.0 M ???**pH does not indicate concentration because weak acids/bases do not dissociate completely.
4 Acid / Base Titration Apparatus burette clampburetteburetring standerlenmeyerflask
5 amount of standard needed to neutralize the unknown sample Equivalence pointamount of standard needed to neutralize the unknown samplemoles H+ = moles OH-(pH = 7)Eq. point - defined by balanced reactionEnd pointpoint in the reaction when indicator turns colour.Endpoint - determined by the choice of indicator
6 Goal is to pick the indicator with an end point at the same pH as the equivalence piont
7 Measured amount of unknown concentration is added to the flask.An appropriate indicator is added to theunknown.3. Measured amount of known concentration is added slowly from the buret.The titration is stopped when a colourchange has occurred (end point).Concentration of the acid is calculated.**Titration can also be preformed with a calculated volume of standard in the flask, and the unknown in the buret.
8 Calculate the concentration of hydrochloric acid, if 25 Calculate the concentration of hydrochloric acid, if mL is just neutralized by ml of a mol/L sodium hydroxide solution.NaCl(aq) + H2O(l)HCl(aq) + NaOH(aq)0.150 mol0.04 L= moles NaOH1 L1:1 ratio moles of HCl0.006 mol= M HCl0.025 L
9 What volume of a mol/L solution of carbonic acid is needed to neutralize 30.0 g of sodium hydroxide.H2CO3(aq) + 2 NaOH(aq)Na2CO3(aq) + 2 H2O(l)Molar mass of NaOH = 40.0 g30.0 g1 mole= moles NaOH40.0 g1:2 ratio moles of H2CO3
10 1.5 L of 0.250 mol/L H2CO3 will neutralize 1:2 ratio0.750 mol1 H2CO3= moles H2CO32 NaOH0.375 mol1 L= 1.5 L H2CO30.250 mol1.5 L of mol/L H2CO3 will neutralize30.0 g of NaOH
11 HCl(aq) + NaOH(aq) NaCl(aq) + H2O(l) Determine the concentration of a hydrochloric acid solution using a mol/L solution of NaOHIndicator - phenolphthalein (endpoint turns pink)HCl(aq) + NaOH(aq) NaCl(aq) + H2O(l)
12 HCl(aq) + NaOH(aq) NaCl(aq) + H2O(l) 1. Calculate the moles of base used:0.100 molL= mol NaOH1 L2. Use stoich to determine moles of acid used:1:1 ratio moles of HCl3. Calculate unknown value.mol= M HClL
14 Plotting pH values during a titration gives a titration curve. Type of curve produced accounts for 2 classes of titrations:1. Strong acid titrated with strong base.Strong base titrated with strong acid.2. Weak acid titrated with strong base.Weak base titrated with strong acid.
15 SB - SA Strong w/ Strong titrations produce well defined, steep s-curves
16 SA - SB Eq point is the centre of the steepest portion of the curve Eq point is at a pH = 7
17 WA - SBStrong w/ weak titrations produce sloppy s-curves
18 WB - SA Eq point not at pH = 7 due to secondary reaction with acidic or basic salt
19 CAN YOU / HAVE YOU?Calculate the concentration or volume of an acid or base from the concentration and volume of an acid or base required for neutralization.Using a standardized acid or base, determine the concentration of an unknown base or acid.Additional KEY Termsstandard solution equivalence pointend point titration