What is meant by limiting reagent? by excess reagent? by hydrate? by proceeds to completion?

Answer 1

A limiting reagent is the chemical that "limits" the reaction, usually because there is less of it than the other chemicals. Excess reagent means that the amount of chemical is too much for the reaction, or when the reaciton completes, there will be more of the chemical left over. Hydrate means there is water in the chemical, not just pure chemical. And to complettion just means allowing the reaction to proceed until the reaction stops.