8.00 g of calcium chloride, CaCl2, is dissolved in 1.000 Kg of water.

Question

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?
moles = grams/molar mass = ?

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

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

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?
moles Ca^2+ = moles CaCl2
moles Cl^- = moles CaCl2 x 2 = ?