Use this equation to answer the questions below: Br2 + Cl2 → 2BrCl.

a. How many moles of BrCl form when 2.74 mol Cl2 react with excess Br2?
b. How many grams of BrCl form when 318.5 g Cl2 react with excess Br2?
c. How many grams of Br2 are needed to react with 3.36 × 1025 molecules Cl2?

1 answer

Br2 + Cl2 → 2BrCl. Assuming the reaction occurs above 99.9%, then
a. 2.74 mols Cl2 x (2 mols BrCl/1 mol Cl2) = 2.74 x 2 = ?
b. mols Cl2 =grams/molar mass = 318.5/71 = about 5 but you should be more accurate.
Then 5 mols Cl2 x 2 (from part a) = 10 mols BrCl.Then grams BrCl = mols BrCl x molar mass BrCl = ? Note the about phrase. I estimated. Close but not exactly accurate.
c. Convert 3.36E25 molecules to moles. 3.36E25/6.02E23 = mols Cl2. Then follow the procedure in b.
Post your work if you get stuck.