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Chemistry vocabulary · Reactions and Equations

Reactant

Meaning in chemistry, with examples

nounCore term

In chemistry, reactant means: A starting substance that is used up or changed in a chemical reaction. In an equation, these substances are written to the left of the arrow.

In Turkish: giren madde, tepken, reaktan

How it is used

Used in textbooks and reports; in synthesis labs people often say 'starting material' or 'reagent' instead. You mix, add or consume reactants, and the one left over at the end is the 'reactant in excess'.

Example sentences

  1. In this reaction, both reactants are colorless but the product is bright yellow.

  2. The reactants must be completely dry before you mix them.

Common collocations

  • reactant in excess
  • consume a reactant
  • reactants and products
  • starting material
  • productA substance formed in a chemical reaction. In an equation, these new substances are written to the right of the arrow.
  • chemical equationA short written description of a reaction using formulas and symbols, with the reactants on the left, an arrow in the middle and the products on the right.
  • limiting reagentThe reactant that runs out first in a reaction. It decides the maximum amount of product that can form; the other reactants are left over in excess.
  • stoichiometryThe calculation of the amounts of reactants and products in a reaction, using the mole ratios from the balanced equation.

More terms: Reactions and Equations

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