Final answer:
To find the mass of excess reagent remaining after a reaction, determine the balanced chemical equation, convert quantities to moles, find the limiting reactant, calculate the product formed, and subtract the consumed excess reagent from the original amount.
Step-by-step explanation:
To calculate the mass of the excess reagent remaining after a chemical reaction, one must first understand stoichiometry, which is the calculation of the quantities of reactants or products in a chemical reaction using the relationships found in a balanced chemical equation. The following steps are typically employed:
- Determine the balanced chemical equation for the chemical reaction.
- Convert all given information into moles, usually by using molar mass as a conversion factor.
- Calculate the mole ratio from the given information and compare it to the actual ratio to determine the limiting reactant and excess reactant.
- Use the amount of limiting reactant to calculate the amount of product produced.
- Subtract the mass of excess reactant consumed (calculated from the mole ratio) from the total mass of excess reactant given to find the amount of remaining excess reactant.
It's important to remember that the limiting reactant is the one that will run out first and stop the reaction, whereas the excess reactant is the one that will be left over.