Question

Given the following mixture of two compounds 20.00 g of X (MW =83.00 g/mol) and 880.00 mL of Y (72.00 g/mol))(density 0.881 g/mL), calculate the molarity of X.

Answer 1

The molarity is the number of moles of solute per litre of solution: $molarity=n(solute)/V(solution)$

In our case compound X is solute. First we calculate the number of moles of X:

$n(X)=m/MW=20/83=0.241~mol$

Volume of solution is the available volume of compound Y (in litres):

$V=880~ml=0.880~L$

$molarity=0.241/0.880=0.274~mol/L$