Question

8.00 g of calcium chloride, CaCl2, is dissolved in 1.000 Kg of water.
Molecular weights, Ca= 40 g/ mol, Cl= 35.5 g/ mol, H= 1 g/mol, O= 16 g/ mol
Density = 1 g/cm3
a. How many moles of CaCl2 are in solution?
b. How many moles of water are present?
c. Find the number of H atoms in water molecules.
d. Assume that the ionic compound, CaCl2, separates completely into Ca2+ and
Cl- ions when it dissolves in water. How many moles of each ion are present in
the solution?

Answer 1

a. How many moles of CaCl2 are in solution?
<b><i> moles = grams/molar mass = ? </b></i>

b. How many moles of water are present?
<b><i> moles = grams/molar mass = ?</b></i>

c. Find the number of H atoms in water molecules.
<b><i> # H atoms = moles H2O x 2 x 6.02E23 = ? </b></i>

d. Assume that the ionic compound, CaCl2, separates completely into Ca2+ and
Cl- ions when it dissolves in water. How many moles of each ion are present in
the solution?
<b><i> moles Ca^2+ = moles CaCl2
moles Cl^- = moles CaCl2 x 2 = ? </b></i>