Question: Write the chemical reaction when lithium hydroxide is mixed with carbonic acid.

Step 1: write out the reactantsLiOH(aq) + H2CO3(aq)

Step 2: determine products … H2O and Li2(CO3)LiOH(aq) + H2CO3(aq) Li2CO3(aq) + H2O(l)

Step 3: balance the equation2LiOH(aq) + H2CO3(aq) Li2CO3(aq) + 2H2O(l)

lithium hydroxide + carbonic acid lithium carbonate + water

Writing neutralization equationsWriting neutralization equationsWhen acids and bases are mixed, a salt forms

NaOH + HCl H2O + NaCl base + acid water + saltCa(OH)2 + H2SO4 2H2O + CaSO4

a) iron(II) hydroxide + phosphoric acidb) Ba(OH)2(aq) + HCl(aq)

c) calcium hydroxide + nitric acidd) Al(OH)3(aq) + H2SO4(aq)

e) ammonium hydroxide + hydrosulfuric acidf) KOH(aq) + HClO2(aq)

AssignmentAssignment

Write balanced chemical equations for these neutralization reactions. Under each compound give the correct IUPAC name.

a) 3Fe(OH)2(aq) + 2H3PO4(aq) Fe3(PO4)2(aq) + 6H2O(l) iron(II) hydroxide + phosphoric acid iron (II) phosphate

b) Ba(OH)2(aq) + 2HCl(aq) BaCl2 (aq) + 2H2O(l) barium hydroxide + hydrochloric acid barium chloride

c) Ca(OH)2(aq) + 2HNO3(aq) Ca(NO3)2(aq) + 2H2O(l) calcium hydroxide + nitric acid calcium nitrate

d) 2Al(OH)3(aq) + 3H2SO4(aq) Al2(SO4)3(aq) + 6H2O(l) aluminum hydroxide + sulfuric acid aluminum sulfate

e) 2NH4OH(aq) + H2S(aq) (NH4)2S(aq) + 2H2O(l) ammonium hydroxide+ hydrosulfuric acid ammonium sulfide

f) KOH(aq) + HClO2(aq) KClO2(aq) + H2O(l) potassium hydroxide + chlorous acid potassium chlorite

Calculations involving Neutralization Reactions

Sample Problem 1What volume of 0.250M sulfuric acid, H2SO4

(aq) is needed to react completely with 37.2 mL of 0.650 M potassium hydroxide, KOH (aq)?

1. Step 1. Write a balanced equation for the reaction.

H2SO4(aq) + 2KOH(aq) 2H20(l) + K2SO4 (aq)

Step 2. Using the information provided, calculate the number of moles of base.

c = .650 mol/LV= 37.2 mL = 0.0372 Ln = cV = (.65 mol/L)(0.0372L) = 0.02418 mol

H2SO4(aq) + 2KOH(aq) 2H20(l) + K2SO4 (aq)

H2SO4(aq) + 2KOH(aq) 2H20(l) + K2SO4 (aq)

Step 3. Determine the number of moles of H2SO4 needed to neutralize the lithium hydroxide. (Use mole ratio, if necessary)

=0.02418mol KOH X 1 mol H2SO4

2 mol KOH

=0.01209 mol H2SO4

Step 4. Find the volume of H2SO4(aq) based on the moles and concentration of H2SO4 solution.

c= n/VV= n/c = 0.01209 mol/0.250M = 0.0484 L = 48.4 mL

H2SO4(aq) + 2KOH(aq) 2H20(l) + K2SO4 (aq)

Problem 2: A 25.0 mL sample of hydrochloric acid is titrated with 1.00 mol/L NaOH. The end

point is reached when 67.5 mL of base has been added. Calculate the concentration of

the acid in mol/L.

1. Step 1. Write a balanced equation for the reaction.

HCl(aq) + NaOH(aq) H20(l) + NaCl(aq)

HCl(aq) + NaOH(aq) H20(l) + NaCl(aq)

Step 2. Using the information provided, calculate the number of moles of base.

c = 1.00 mol/LV= 67.5 mL = 0.0675 Ln = cV = (1.00 mol/L)(0.0675L) = 0.0675 mol

HCl(aq) + NaOH(aq) H20(l) + NaCl(aq)

Step 3. Determine the number of moles of HCl needed to neutralize the sodium hydroxide. (Use mole ratio, if necessary)

In this case nA= nB = 0.0675 mol

HCl(aq) + NaOH(aq) H20(l) + NaCl(aq)

Step 4. Find the concentration of HCl(aq) based on the moles and volume of HCl solution.

c= n/V = 0.0675 mol/0.0250L = 2.70 mol/L

Calculate the % of HCl (as m/m) in the solution, given that its density is 1.100

g/mL

2.70 mol HCl1.00 L of solution

m=nM =(2.70 mol)(36.36g/mol) = 98.4 g

m=DV =(1.100g/mL)(1000mL) = 1100 g

% = 98.4g x 100 1100g = 8.95%

Titration

• Titrations are a chemical procedure involving the addition of a solution of known concentration. The objective is to determine the point in the reaction when the moles of the known solution is equal to the moles of the unknown solution.

• The concentration of the unknown solution can be determined by:

• Concentrationunknown =Volumeknown x Concentrationknown Volumeunknown

Titration Terminology

• Titrant-solution of known concentration. It is added slowly using a burette

• Sample-solution of unknown concentration. It is contained in a flask

• Primary Standards/Solutions- Solution of know accurate concentrations that are used as titrants.

Titration Terminology

• Indicator-A solution that changes color at the equivalence point.

• Equivalence Point (Stoichiometric Point)-the amount of titrant required for a complete reaction to occur. (chemically equivalent amounts have reacted).

• Endpoint-The point in a titration where a measurable change occurs (indicator change, pH change)