Chemical Equation Question Type¶

Students balance chemical equations with proper stoichiometric coefficients.

Basic Syntax¶

[chemequation]
answer = 2 H2 + O2 = 2 H2O;

Options¶

`answer` (required)¶

The balanced chemical equation.

[chemequation]
answer = CH4 + 2 O2 = CO2 + 2 H2O;

`type`¶

balance (default) — Student provides coefficients, formula given
predict — Student predicts products (given reactants)

[chemequation]
answer = 2 Na + 2 H2O = 2 NaOH + H2;
type = balance;

Examples¶

Combustion Reaction¶

Balance the equation: C_xH_y + O_2 → CO_2 + H_2O

[chemequation]
answer = C6H12O6 + 6 O2 = 6 CO2 + 6 H2O;
type = balance;

Acid-Base Neutralization¶

Balance: H_2SO_4 + NaOH → Na_2SO_4 + H_2O

[chemequation]
answer = H2SO4 + 2 NaOH = Na2SO4 + 2 H2O;
type = balance;

Decomposition Reaction¶

Balance: CaCO_3 → CaO + CO_2

[chemequation]
answer = 1 CaCO3 = 1 CaO + 1 CO2;
type = balance;

Grading¶

The system: 1. Parses the student's equation 2. Verifies atoms are balanced on both sides 3. Checks coefficient accuracy 4. Returns Correct if balanced, Incorrect otherwise

Tips¶

Provide unbalanced equation: Students fill in coefficients
Start with simple equations: Two or three compounds before complex multi-step reactions
Show state labels: (s), (l), (g), (aq) if needed for clarity
Avoid unusual elements: Stick to C, H, O, N, S, P, Na, Ca, Fe, etc.

Notation¶

Use element symbols: H, C, O, Na, Ca
Use subscripts as numbers: H2O, CaCO3, not H₂O
Separate compounds with +
Use = for the reaction arrow
Coefficients are optional (default is 1)