IB DP Chemistry: Command terms and keywords

IB Diploma Programme Chemistry (SL and HL) uses the standard IB command terms. Chemistry emphasises Calculate, Deduce, Explain and Suggest. Precise chemical terminology and correct units are essential.

Key command terms for Chemistry

Command term	What to do	Common mistake
State	Short answer	Overwriting
Define	Precise meaning	Vague definition
Write	Give equation or expression	Incomplete equation
Calculate	Numerical answer; show working; units	No working; wrong units
Deduce	Conclusion from data/evidence	Guessing
Describe	Account of observations/process	Adding explanation
Explain	Reasons; mechanisms; “because”	Only describing
Suggest	Apply to context; propose	Textbook recall only
Predict	Expected result from knowledge	Guess
Compare	Similarities and/or differences	Listing separately
Evaluate	Strengths and limitations	Description only
Design	Plan experiment or method	Vague procedure

Chemistry keywords (use correctly)

Term	Use correctly	Avoid
Mole	Amount of substance; 6.02 × 10²³ particles	”Molecules”
Concentration	mol dm⁻³ or g dm⁻³	”Strength”
Enthalpy	Heat change at constant pressure	”Energy”
Activation energy	Minimum energy for reaction	”Energy barrier”
Equilibrium	Dynamic; rates equal	”Static”
Le Chatelier	System opposes change	”Shifts” (say why)
Oxidation	Loss of electrons	”Gain of oxygen”
Reduction	Gain of electrons	”Loss of oxygen”
Ionic bond	Electrostatic attraction	”Transfer”
Covalent bond	Shared pair of electrons	”Sharing” (add “pair”)
Electronegativity	Tendency to attract electrons	”Charge”
Isotope	Same protons, different neutrons	”Same element”
Empirical formula	Simplest ratio	Molecular formula
Rate of reaction	Change in concentration per unit time	”Speed”

Tips for Chemistry exams

1. Calculate—show working; include units (mol, dm³, kJ mol⁻¹)
2. Deduce—use data; show reasoning
3. Explain—mechanisms; electron movements; energy changes
4. Suggest—apply to unfamiliar context; propose reasonable answer
5. State—short; no expansion
6. Past papers—check mark schemes for acceptable wording

How Tutopiya helps

Tutopiya supports IB DP Chemistry (SL and HL). Explore IB resources or book a free trial.

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Based on IB Diploma Programme Chemistry subject guide. Check the guide for syllabus-specific command terms.

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