What is the freezing point of a solution that contains 36.0 g of glucose in 500.0 g of water (kf for water is 1.86c/m. the molar mass of glucose is 180.0 g per mole.)
i have been trying to solve this for 2 days, but i can't find a good enough explanation to understand it.

This freezing point business is usually based on molality, that is moles solute per kilogram of solvent. 

molality = freezing point depression over Kf 

In this case molality -10.3 degrees over -1.85 degrees Kf = 5.53 molal 

This 5.53 molal solution is made up of l000 gms water and 5.53 moles glucose at 180 grams per mole for a total mass of 1997 grams 

It volume would be l997 gms over 1.50 gms/ml or 1331 ml 

We know that we have 5.53 moles of glucose dissolved in l331 ml of solution so now we can find how many moles of glucose in l000 ml or one liter of solution and this will be our Molarity 

5.53 moles glucose over l331 ml = X moles glucose over l000 ml solution 

cross multiply and solve for X moles glucose per liter solution 

X = 4.15 moles glucose per liter = 4.15 Molar

Mass is the amount of matter in an object.  weight is the measurement of the pull of gravity on an object.  say for example, you travel to the moon which has a different gravitational field compared to the gravitational field of earth. (gravitational fields: earth = 1, moon = 0.165)  now when you are on the moon, the pull of gravity on you is different than on the earth. and as weight is the measurement of the pull of gravity on an object, that means yes, your weight can and will change on the moon.  however, on the moon, on earth or even on jupiter, the amount of mass inside of you remains the same. meaning your physical mass remains constant.  in conclusion it is possible for your weight to change as your mass remains constant.