Answer to Question #99059 in General Chemistry for Megan

Question

How do I find the molarity of the excess after the reaction has taken place if I am given the starting molarity and amount in L of the reactants?

Answer 1

1. Write the chemical equation.
2. Calculate the moles of product from the first reactant.
3. Calculate the moles of product from the second reactant.
4. Identify the limiting reactant and the excess reactant.
5. Calculate the mass of excess reactant used up.
6. Calculate the mass of unused excess reactant.
7. Calculate the mass of limiting reactant needed to react with the unused excess reactant.
8. Molarity is the number of moles of solute per liter of solution, which can be calculated using the following equation:

Molarity = moles of solution / L of solution

Molar c​oncentration can be used to convert between the mass or moles of solute and the volume of the solution.