Question

Use the equation below to answer the questions
that follow.
Br2 + Cl 2 ⎯→ 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
239.7 g Cl2 react with excess Br2?
c. How many grams of Br2 are needed to
react with 4.53 × 1025 molecules Cl2?

Answer 1

a)
Use the coefficients in the balanced equation to convert moles of one specie to moles of another.
2.74 mol Cl2 x (2 moles BrCl/1 mole Cl2) = 2.74 x (2/1) = ??

b)
Convert 239.7 g Cl2 to moles. moles = grams/molar mass.
Convert moles Cl2 to moles BrCl.
Finally, convert moles moles BrCl to grams. g = moles x molar mass.

c) Follow the same procedures remembering that there are 6.022 x 10^23 molecules in a mole.
Post your work if you get stuck.