Comprehensive Chemistry: Solutions, Solubility, and Colligative Properties

What is the molarity of 2.7 mol in 5.0 L of water?

0.54 M

How many moles of NaF are in 200 mL of a 0.45 M solution?

0.090 mol

What volume is needed to dissolve 100 g of FeBr₂ for a 0.25 M solution?

1.85 L

What is the dilution formula?

M₁V₁ = M₂V₂

Give an example of a strong electrolyte.

NaCl — fully dissociates into ions.

What happens to concentration when a solution is saturated?

Reaches maximum — no more solute can dissolve.

What is a homogeneous mixture?

Uniform throughout, same phase (e.g., salt water).

What is a heterogeneous mixture?

Not uniform, different phases visible (e.g., oil and water).

What is a solution?

Homogeneous mixture of solute + solvent.

What is a solute?

Substance being dissolved (lesser amount).

What is a solvent?

Substance doing the dissolving (greater amount, e.g., water).

What is an electrolyte?

Dissociates into ions in water → conducts electricity.

What is a strong electrolyte?

100% dissociation (ionic compounds, strong acids).

What is a weak electrolyte?

Partial dissociation (weak acids).

What is a non-electrolyte?

No dissociation → no conductivity (sugar, ethanol).

What is dissociation?

Ionic compounds break into ions in water.

What is solvation?

Process of solvent surrounding solute particles.

What is hydration?

Solvation when water is the solvent.

What is the heat of solution?

Total energy change during dissolving.

What factors increase the dissolving rate?

Agitation (stirring), ↑ surface area (crush), ↑ temperature.

What is an unsaturated solution?

Can dissolve more solute.

What is a saturated solution?

Maximum solute dissolved → equilibrium.

What is a supersaturated solution?

Holds more than saturated → unstable.

What does 'like dissolves like' mean?

Polar dissolves polar, nonpolar dissolves nonpolar.

How does gas solubility change with temperature?

Decreases as temperature increases.

How does gas solubility change with pressure?

Increases as pressure increases (Henry's Law).

How do you read a solubility curve?

On line = saturated, below = unsaturated, above = supersaturated.

Which solubility decreases as temperature rises?

Gases (e.g., NH₃, CO₂).

What is the definition of molarity (M)?

Moles solute per liter solution → M = mol/L.

What is the molarity trick?

ALWAYS convert mL to L first! (÷1000).

What is the definition of molality (m)?

Moles solute per kg solvent → m = mol/kg.

What is the difference between molarity and molality?

M uses L of solution, m uses kg of solvent.

What is the formula for percent mass/volume?

(Mass solute / Volume solution) × 100%.

What are colligative properties?

Depend on number of solute particles, not identity.

What are the four colligative properties?

Vapor pressure lowering, boiling point elevation, freezing point depression, osmotic pressure.

What is the Van't Hoff factor (i)?

Number of particles per formula unit (NaCl → i=2, glucose → i=1).

What is the boiling point elevation formula?

ΔT_b = i × K_b × m (K_b water = 0.52 °C/m).

How do you calculate the new boiling point?

BP = 100°C + ΔT_b.

What is the freezing point depression formula?

ΔT_f = i × K_f × m (K_f water = 1.86 °C/m).

How do you calculate the new freezing point?

FP = 0°C - ΔT_f.

What is the new molarity after diluting a 12 M solution from 0.50 L to 1.0 L?

6.0 M.

How many grams of KF are needed to make a 2.00 M solution in 1.00 L? (MM KF=58 g/mol)

116 g.

Which solution is more concentrated: 0.1 mol/400 mL or 0.4 mol/100 mL?

0.4 mol/100 mL.

How do you determine which salt is most soluble at 60°C?

Compare g/100g water → highest number = most soluble.

How many grams of KClO₃ saturate 100 g of water at 40°C?

~16 g.

How much NaNO₃ precipitates when cooled from 60°C to 10°C?

~44 g.

Which KI solution freezes at the lowest temperature?

Highest molality → 2 mol KI in 500 g water.

Which compound is least soluble at 20°C according to the solubility curve?

KClO₃ (lowest on graph).

Which compound is most affected by temperature according to the solubility curve?

KNO₃ (steepest slope).

Which compound is least affected by temperature according to the solubility curve?

NaCl (flattest slope).

What is a common mistake regarding mL to L conversion?

Always ÷1000 before calculating molarity.

What is a common mistake with the Van't Hoff factor?

Count ions! NaCl=2, CaCl₂=3, glucose=1.

What is a common mistake regarding saturated vs. unsaturated solutions?

Saturated = max dissolved, can't add more.

What is a common mistake regarding gas vs. solid solubility with temperature?

Solids ↑ with heat, gases ↓ with heat.

What is a common mistake regarding molarity vs. molality?

M = mol/L solution, m = mol/kg solvent.