Molarity
What is Molarity?
Molarity = moles solute / L solution
Classify the following as acid, base, or neither:
a) HBr
b) NaOH
c) NaCl
HBr = Acid
NaOH = Base
NaCl = Neither (salt)
Will a precipitate form when NaCl(aq) and AgNO₃(aq) are mixed?
Yes, AgCl forms a precipitate.
What is a spectator ion?
An ion that appears unchanged on both sides of a reaction and cancels out in the net ionic equation.
50.0 mL of 1.00 M HCl reacts with 40.0 mL of 1.00 M NaOH.
HCl + NaOH → NaCl + H₂O
Which reactant is limiting?
NaOH
How many moles are in 2.0 L of a 0.50 M NaCl solution?
1.0 mol
Which is the stronger acid?
a) HCl
b) CH₃COOH
HCl (strong acid)
CH₃COOH is weak.
Will a precipitate form when KNO₃(aq) and NaCl(aq) are mixed?
No,
All nitrates (NO₃⁻) are soluble.
All alkali metal salts (Na⁺, K⁺) are soluble.
Write the net ionic equation for:
NaCl(aq) + AgNO₃(aq) → AgCl(s) + NaNO₃(aq)
Na⁺ + Cl⁻ + Ag⁺ + NO₃⁻ → AgCl(s) + Na⁺ + NO₃⁻
Ag⁺(aq) + Cl⁻(aq) → AgCl(s)
75.0 mL of 0.80 M AgNO₃ reacts with 50.0 mL of 1.20 M NaCl.
AgNO₃ + NaCl → AgCl(s) + NaNO₃
How many moles of AgCl form?
0.060 mol AgCl
How many milliliters of 0.75 M HCl are needed to make 0.150 moles of HCl?
200 mL
Identify each as strong electrolyte, weak electrolyte, or non-electrolyte:
a) HNO₃
b) NH₃
c) C₆H₁₂O₆ (glucose)
HNO₃ = Strong electrolyte
NH₃ = Weak electrolyte
Glucose = Non-electrolyte
When CaCl₂(aq) and Na₂CO₃(aq) are mixed, does a precipitate form?
If yes, name it.
Yes.
CaCO₃
Write the net ionic equation for:
CaCl₂(aq) + Na₂CO₃(aq) → CaCO₃(s) + 2NaCl(aq)
Ca²⁺ + 2Cl⁻ + 2Na⁺ + CO₃²⁻ → CaCO₃(s) + 2Na⁺ + 2Cl⁻
Ca²⁺(aq) + CO₃²⁻(aq) → CaCO₃(s)
100.0 mL of 0.50 M H₂SO₄ reacts with 150.0 mL of 0.40 M NaOH.
H₂SO₄ + 2NaOH → Na₂SO₄ + 2H₂O
Which reactant is limiting?
NaOH
100 mL of 4.3 M NaCl is diluted to 250 mL. What is the new concentration?
M1V1=M2V2
1.72 M
Which of the following are strong bases?
a) KOH
b) Ba(OH)₂
c) Al(OH)₃
d) NaOH
Strong bases: KOH, Ba(OH)₂, NaOH
Two solutions are mixed: BaCl₂(aq) and Na₂SO₄(aq).
Will a precipitate form?
What is it?
Yes, BaSO₄
Write the net ionic equation for:
BaCl₂(aq) + Na₂SO₄(aq) → BaSO₄(s) + 2NaCl(aq)
Ba²⁺ + 2Cl⁻ + 2Na⁺ + SO₄²⁻ → BaSO₄(s) + 2Na⁺ + 2Cl⁻
Ba²⁺(aq) + SO₄²⁻(aq) → BaSO₄(s)
200.0 mL of 0.60 M HCl reacts with 150.0 mL of 0.50 M Ca(OH)₂.
2HCl + Ca(OH)₂ → CaCl₂ + 2H₂O
Identify the limiting reactant.
How many grams of CaCl₂ form?
(Molar mass CaCl₂ = 111 g/mol)
HCl
6.66 g CaCl₂
How many mL of 0.50 M HCl are required to completely react with 4.0 g of NaOH?
(Molar mass NaOH = 40.0 g/mol)
HCl + NaOH → NaCl + H₂O
200 mL
Classify each substance as:
• Strong acid
• Weak acid
• Strong base
• Weak base
• Non-electrolyte
a) H₂SO₄
b) HF
c) LiOH
d) NH₃
e) C₂H₅OH (ethanol)
H₂SO₄ = Strong acid
HF = Weak acid
LiOH = Strong base
NH₃ = Weak base
Ethanol = Non-electrolyte
Two aqueous solutions are mixed:
• Lead(II) nitrate
• Potassium iodide
Will a precipitate form?
Write the formula of the precipitate (Net ionic equation).
Yes, Pb²⁺ + 2I⁻ → PbI₂
Write the net ionic equation for:
HCl(aq) + NaOH(aq) → NaCl(aq) + H₂O(l)
H⁺ + Cl⁻ + Na⁺ + OH⁻ → Na⁺ + Cl⁻ + H₂O(l)
H⁺(aq) + OH⁻(aq) → H₂O(l)
125.0 mL of 0.90 M BaCl₂ reacts with 100.0 mL of 1.10 M Na₂SO₄.
BaCl₂ + Na₂SO₄ → BaSO₄(s) + 2NaCl
Identify the limiting reactant.
How many grams of BaSO₄ form?
(Molar mass BaSO₄ = 233 g/mol)
Na₂SO₄
25.6 g BaSO₄