Question

1. An aqueous solution of calcium chloride, CaCl2, is 3.464 M and has a density of 1.2816 g cm-3. Assuming you have 1 liter of this solution answer the following questions.

a) Use the density to calculate the mass of the solution 1281.6 grams of solution

b) Given that you have 1 liter of solution how many moles of CaCl2 are in the solution? mol CaCl2

c) Calculate the mass of CaCl2 in the solution grams CaCl2

d) Determine the mass of water in the solution. grams of H2O

2. Calculate the weight percent of CaCl2 in the solution. weight % CaCl2

3. Calculate the molality of CaCl2 in the solution. m CaCl2

4. Calculate the mol fraction of CaCl2 in the solution. (mol fraction CaCl2)

5. Calculate the mol fraction of Cl- ion in the solution. (mol fraction Cl-)

Answer 1

a) Use the density to calculate the mass of the solution 1281.6 grams of solution

mass of solution = d*v

    = 1.2816*1000 = 1281.6 grams

b) Given that you have 1 liter of solution how many moles of CaCl2 are in the solution? mol CaCl2

Molarity means n moles in 1 lit solution .

No of mole of cacl2 = 3.464 mol

c) Calculate the mass of CaCl2 in the solution grams CaCl2

mass of cacl2 = 3.464*110.98 = 384.434 grams

d) Determine the mass of water in the solution. grams of H2O

mass of water = 1281.6 - 384.434   = 897.166 grams

2. Calculate the weight percent of CaCl2 in the solution. weight % CaCl2

weight percent = (384.434 / 1281.6)*100 = 30%

3. Calculate the molality of CaCl2 in the solution. m CaCl2

molality = (384.434/110.98)*(1000/897.166)

   = 3.86 molal

4. Calculate the mol fraction of CaCl2 in the solution. (mol fraction CaCl2)

No of mole of water = 897.166/18 = 49.84 mol

No of mole of cacl2 = 384.434/110.98 = 3.46 mol

molefraction of cacl2 = 3.46/(3.46+49.84) = 0.064

5. Calculate the mol fraction of Cl- ion in the solution. (mol fraction Cl-)

molefraction of cl- = (3.46*2)/(49.84+3.46*2) = 0.122