Chemical equation

Why this shape

An equation written and balanced: the core skill of chemistry, marked by rule.

An example. Balance: H₂ + O₂ → H₂O

What it is

Specialised shapes fit particular subjects: a maths expression typed and checked, working shown step by step, code read or written, a chemical equation balanced, notes on a staff, cells in a grid, a number scored by how close it is, a passage highlighted.

Why it is needed

Every field has a form of answer that the general shapes mangle: an equation is not a word, a proof is not a paragraph, a program is not prose. A shape built for the form marks what the field marks and nothing else, and it lets Procto AI write questions in the form the subject uses.

When to use it

Use the maths shapes for calculation and working, the code shapes for programming courses and hiring, the chemistry shape for equations, estimation wherever a range is the honest answer, and highlighting for reading with evidence.

How to write one well

State the form the answer must take: an expression, a number to a given precision, a balanced equation, a language. Give the tolerance where a range is acceptable. For working, mark each step in the rubric so partial credit is fair.

For chemical equation in particular. Accept the balanced equation in any valid coefficient set.

Mistakes to avoid

Accepting one written form of an expression when several are equivalent. No tolerance on a measured answer. Code questions that depend on formatting. A highlight that could reasonably span more or fewer words.

How EdProcto marks it

Expressions, numbers and single-form answers are marked by rule, with tolerances and half-credit tolerances where you set them. A typed expression or chemical equation is compared sign for sign, with spacing ignored, so each form you accept is listed, and a slip that would be forgiven in a word is never forgiven here; working and code are marked by a reader against your rubric, step by step.