Molarity and Freezing Point Depression

Assignment 22
1. Molarity is given by moles of solute divided by volume of solution
Molarity =moles of the solute/volume of the solution
3.5 moles / 5L = 0.7M
2. First calculate the number of moles which is given by molarity multiplied by the volume
of the solution
1.50x0.500 =0.75 moles
Mass is given by molecular mass of KF multiplied by the number of moles, therefore
mass will be 0.75x58.0967032 =43.5g
3. First calculate the number of moles of hydrochloric acid which is given by
6Mx225ml=1350 moles
To get the final volume you divide the number of moles by the final molarity is given by
1350/1.5 =900ml
4. Allowing the solution to undergo evaporation makes it more concentrated since the
solvent evaporates leaving the solute behind. Evaporating will reduce the solvent and
increase the solubility of the solute as temperature increases.
5. Chlorides of all metals are soluble in water except silver and it will be in solid form while
all salts of sodium are soluble in water thus sodium chloride will be in aqueous form thus
the equation will be
NaNO3 (aq) +AgCl (s)
6. We say the solution is saturated-saturated means no more solute can be dissolved in the
solvent. It is understood that saturation of the solution has been achieved when any
additional substance that is added results in a solid precipitate or is let off as a gas.
7. Sodium chloride (NaCl) dissociates to form one sodium ion and one chloride ion while
magnesium bromide (MgBr2) dissociates to form 2 magnesium ions and one bromide ion
and calcium nitrate dissociates to form one calcium ion and 2 nitrate ions
8. The net ionic equation is a chemical equation for a reaction which lists only those species
participating in the reaction leaving out the spectator ions thus choice b represents the net
ionic equation.