"a chemical substance that is present at the start of a chemical reaction"@en-us . . . . . . . . . "14694765-n"^^ . "114694765"^^ . . "0"^^ . . . . . "0"^^ . "reactant"^^ . "113854683"@en-us . "a chemical substance that is present at the start of a chemical reaction"@en-us . . "reactant"@en-us . . .