<Dd> <Dl> <Dt> X ⋅ + R − H ⟶ X − H + R ⋅ (\ displaystyle (\ ce ((X .) + (R-H) -> (X-H) + (R .)))) </Dt> <Dt> R ⋅ + X 2 ⟶ R − X + X ⋅ (\ displaystyle (\ ce ((R .) + (X2) -> (R (-) X) + (X .)))) </Dt> <Dd> Reactions during the chain reaction of radical substitution </Dd> </Dl> </Dd> <Dl> <Dt> X ⋅ + R − H ⟶ X − H + R ⋅ (\ displaystyle (\ ce ((X .) + (R-H) -> (X-H) + (R .)))) </Dt> <Dt> R ⋅ + X 2 ⟶ R − X + X ⋅ (\ displaystyle (\ ce ((R .) + (X2) -> (R (-) X) + (X .)))) </Dt> <Dd> Reactions during the chain reaction of radical substitution </Dd> </Dl> <Dt> X ⋅ + R − H ⟶ X − H + R ⋅ (\ displaystyle (\ ce ((X .) + (R-H) -> (X-H) + (R .)))) </Dt> <Dt> R ⋅ + X 2 ⟶ R − X + X ⋅ (\ displaystyle (\ ce ((R .) + (X2) -> (R (-) X) + (X .)))) </Dt>

A change in the composition of matter always occurs during a chemical reaction