Solutions Cheatsheet

Cheat Codes & Shortcuts

• Solution: Homogeneous mixture of solute(s) in solvent.
• Solute: Substance dissolved in solvent.
• Solvent: Substance in greatest amount, does the dissolving.
• Molarity (\( M \)): Moles of solute/liter of solution.
• Molality (\( m \)): Moles of solute/kg of solvent.
• Normality (\( N \)): Equivalents of solute/liter of solution.
• Mass %: \( \frac{\text{Mass of solute}}{\text{Mass of solution}} \times 100 \)
• ppm: Parts per million.
• Henry’s Law: \( p = k_H x \) – gas solubility proportional to partial pressure.
• Raoult’s Law: Vapor pressure lowering relates to solute mole fraction.

Quick Reference Table

Term	Formula / Description	Example / Note
Molarity	\( M = \frac{\text{moles of solute}}{\text{volume of solution in L}} \)	1M NaCl: 1 mole NaCl in 1L solution
Molality	\( m = \frac{\text{moles of solute}}{\text{kg of solvent}} \)	1m NaCl: 1 mole NaCl in 1kg solvent
Mass %	\( \frac{\text{mass of solute}}{\text{mass of solution}} \times 100 \)	10g NaCl in 90g H2O = 10%
ppm	\( \frac{\text{mass of solute}}{\text{mass of solution}} \times 10^6 \)	1 ppm = 1mg/L water
Raoult's Law	\( p_{solvent} = p^0_{solvent} x_{solvent} \)	Lowering vapor pressure in solution
Henry's Law	\( p = k_H x \)	Solubility of CO2 in soda

Advice

Solutions Quick Tips

• Convert: g to mol using molar mass, mL to L dividing by 1,000.
• For dilute solutions: Molarity ≈ molality.
• Raoult’s Law: Applies best to ideal solutions.
• Henry’s Law: Higher pressure increases gas solubility in liquid.
• Dilution: Use \( M_1 V_1 = M_2 V_2 \) for mixing.

Solutions Speed Quiz

Test your speed with 5 solutions questions! You have 30 seconds per question.