Name: _____________________________________________
Date:___________________________
Homework 4 = OPTIONAL!!! DO NOT TURN THIS IN!!!!
1.) Given the following [H+1] concentrations, calculate pH - indicate if it is acidic, basic, or neutral
a. [H+1] = 1.00 x 10-4
pH = 4.00
b. [H+1] = 2.24 x 10-3 pH = 2.65
acidic
acidic
c. [H+1] = 9.76 x 10-8 pH = 7.01 slightly basic!!
2.) Given the following reactions, predict the products using your solubility rules, write ionic
equations for all and net-ionic if necessary. Name each reactant and product! Do not forget to
show phases!
a. _______H3PO4 (aq)
Names:
Ionic:
phosphoric acid
3H+1
(aq)
+
____3___NaOH (aq)
→
sodium hydroxide
___3___H2O (l)
+ ______Na3PO4 (aq)
water
sodium phosphate
+ PO4-3 (aq) + 3Na+1(aq) + 3OH-1(aq) → 3H2O (l) + 3Na+1(aq) + PO4-3 (aq)
Net-ionic: 3H+1 (aq) + 3OH-1 (aq) → 3H2O (l)
b. ___2___HCl (aq)
Names: hydrochloric acid
Ionic: 2H+1
(aq)
+ _______Ba(OH)2 (aq)
barium hydroxide
→
______BaCl2 (aq)
+ __2___H2O (l)
barium chloride
+ 2Cl-1 (aq) + Ba+2(aq) + 2OH-1(aq) → 2H2O (l) + Ba+2(aq) + 2Cl-1 (aq)
Net-ionic: 2H+1 (aq) + 2OH-1 (aq) → 2H2O (l)
water
Names:
c. _______K2CrO4 (aq)
potassium chromate
+ _______Li2SO4(aq)
lithium sulfate
→ ______ Li2CrO4 (aq) + ______K2SO4 (aq)
lithium chromate
potassium sulfate
Ionic: 2K+1 (aq) + CrO4-2 (aq) + 2Li+2 (aq) + SO4-2 (aq) → 2Li+2 (aq) + CrO4-2 (aq)
+ 2K+1 (aq) + SO4-2 (aq)
Net-ionic: none!!! All species are soluble – we could call this a No reaction!
Names:
Ionic:
d. _______H2CO3 (aq)
carbonic acid
+
_______Ba(ClO3)2 (aq) → ______BaCO3 (s) + ___2___ HClO3 (aq)
barium chlorate
barium carbonate
chloric acid
2H+1 (aq) + CO3-2 (aq) + Ba+2 (aq) + 2ClO3-1 (aq) → BaCO3 (s) + 2H+1 (aq) + 2ClO3-1 (aq)
Net-ionic: Ba+2 (aq) + CO3-2 (aq) → BaCO3 (s)
e. _______Na3PO4 (aq) + ______Cr(C2H3O2)3 (aq) → ______CrPO4 (s) + ___3___NaC2H3O2 (aq)
Names: sodium phosphate
chromium (III) acetate
chromium (III) phosphate sodium acetate
Ionic: 3Na+1 (aq) + PO4-3 (aq) + Cr+3 (aq) + 3C2H3O2-1 (aq) → CrPO4 (s) + 3Na+1 (aq) + 3C2H3O2-1 (aq)
Net-ionic: Cr+3 (aq) + PO4-3 (aq) → CrPO4 (s)
3.) If you have 200.00 mL of 6.25 M CuSO4 and you pipet out 10.00 mL of this solution into a 500.00
mL volumetric flask, then dilute to the mark, what is the new concentration of your 500.00 mL
solution? What is the name for CuSO4?
M1V1 = M2V2
10.00 mL = V1
6.25 M = M1
V2 = 500.00 mL
M2 = ???
(10.00 mL)(6.25 M)
500.00 mL
= M2 = 0.125 M
4.) A 65.00 mL portion of phosphoric acid solution is titrated to the endpoint with 43.24 mL of 4.555 M
NaOH. Calculate the Molarity of the acid solution and name each product formed in the balanced
chemical reaction. Assume all H+1 ions in phosphoric acid react.
Step 1: Write a balanced reaction for sodium hydroxide and phosphoric acid!!
3NaOH (aq) + H3PO4 (aq) → Na3PO4 (aq) + 3H2O (l)
Step 2: perform the calculation
4.555 moles NaOH x
1L
1 mole H 3 PO 4
1000mL
1
1L
=
x
x
x 43.24mL x
1L
3 mole NaOH 65.00mL
1000mL
1.010 M phosphoric acid
5.) In a titration, 22.21 mL of 6.24 M hydrochloric acid(aq) neutralizes 80.12 mL of barium hydroxide(aq).
Calculate the Molarity barium hydroxide and name each product formed in the balanced chemical
reaction.
Step 1: write the balanced reaction!
2HCl (aq) + Ba(OH)2 (aq) → 2H2O (l) + BaCl2 (aq)
6.24 moles HCl x
1L
1 mole Ba(OH)2
1000mL
1
1L
=
x
x 22.21mL x
x
1L
80.12mL
1000mL
2 mole HCl
0.865 M Ba(OH)2