Formulas

Question 1

Front (Concept or Quantity)

Answer 1

Back (Formula or Explanation)

Question 2

Relative Atomic Mass (Aᵣ)

Answer 2

Relative Atomic Mass = (Average mass of isotopes of an element × abundance) ÷ 100

Question 3

Relative Molecular Mass (Mᵣ)

Answer 3

Relative Molecular Mass = Sum of relative atomic masses of atoms in the molecule

Question 4

Mole (mol)

Answer 4

Moles = Mass ÷ Molar mass

Question 5

Number of Particles

Answer 5

Number of particles = Moles × Avogadro’s number (6.02 × 10²³)

Question 6

Concentration (mol/dm³)

Answer 6

Concentration = Moles ÷ Volume (in dm³)

Question 7

Volume of Gas (dm³)

Answer 7

Volume = Moles × 22.4 (at STP) or × 24 (at RTP)

Question 8

Empirical Formula

Answer 8

Empirical formula = Simplest whole number ratio of atoms in a compound

Question 9

Molecular Formula

Answer 9

Molecular formula = (Mᵣ ÷ empirical formula mass) × empirical formula

Question 10

Percentage Yield

Answer 10

Percentage Yield = (Actual yield ÷ Theoretical yield) × 100%

Question 11

Percentage Composition

Answer 11

Percentage Composition = (Mass of element ÷ Total molar mass) × 100%

Question 12

Heat Energy (Q)

Answer 12

Q = mcΔT (where m = mass, c = specific heat capacity, ΔT = temperature change)

Question 13

Enthalpy Change (ΔH)

Answer 13

ΔH = Q ÷ Moles of limiting reactant

Question 14

Ideal Gas Equation (basic form)

Answer 14

PV = nRT (used less frequently in CSEC but foundational)

Question 15

pH Calculation

Answer 15

pH = -log₁₀[H⁺]

Question 16

Molar Mass

Answer 16

Molar Mass = Mass ÷ Moles

Question 17

Titration Calculation

Answer 17

n₁V₁ = n₂V₂ (for acid-base neutralization with balanced coefficients)