Answer to Question #219670 in Organic Chemistry for manreet

Question

Calcium chloride is used to melt ice on roads. 

To determine how much calcium chloride has been used, you take a sample of slush from the road to analyze. 

You collect the following data: 

    Mass of empty container: 54.54 g 

    Mass of container and sample of slush: 160.65 g 

Then, you evaporate the water from the solution and determine the mass of the residue to be 3.29 g. What is the percent by mass of CaCl₂ in the slush that was collected? 

Answer 1

Given mass of CaCl2=106.11mg=0.10611 g (Since 1g=1000mg)

molar mass of CaCl2=110.08 g/mol

Therefore moles of CaCl2=mass/molar mass=0.10611g/110.08 g/mol=9.64x10^-4 mol.

Let us take volume of solution=1L

therefore molarity of CaCl2=mol/ volume=(9.64x10^-4 mol)

The concentration or molarity of CaCl2=9.64x10^-4 M =0.96 mM ( Since 1M=1000 mM)

We know that 1ppm=1mg in 1L

Here 100 mg in 1L so the concentration of CaCl2=100 ppm. (Parts-per-million).

= 0.00964/0.10611 × 100

=9.08%