please answer questions 4 and question 5 please

Estimate the freezing point of aqueous solutions of: a) 7.5g fructose (nonelectrolyte) per 100.g of water b) 7.5g potassium bromide (strong electrolyte) per 100.g of water c) 7.5g calcium chloride (strong electrolyte) per 100.g of water 3.Briefly explain why a solution does not have a constant freezing point. 4. Calculate the molar mass of an unknown substance if the freezing point of a solution containing 3.22g of the substance in 100.0g camphor is 177.6C (freezing point of pure camphor = 179.8C) 5. Would you expect the freezing point in question 2 b) to be any different if the solute was thagnesium sulfate? Explain