Problem: How can you make and freeze a solution with a freazing point of exactly -2C?

Question

I need a hypothesis for that...care to help? pleaseeeee :]
heres my entire lab.

and CAIS people...dont tell Miss Ho :]

Material
Large beaker
crushed ice
stirring rod
solute
timing device with a second hand measuring device

Procedure
1. Decide exactly how to define "frozen" in this investigation. (This step is important - without it the challenge could be like a marathon without a finishing line.)
2. Plan your procedure. (Hint: Make an ice bath)
3. Obtain your teacher's go-ahead and try out your procedure.

Answer 1

If you need a specified freezing point, use delta t (2) = Kf * molal *i. If you use NaCl, your i will be 2. So your molal concentration should be equal to 1/Kf (I think it's 1.86 for water). So use a solution that is (.538 * 58.5) grams NaCl in 1 kg of water. Making a tenth of that would be pretty doable.

Answer 2

Adding an impurity such as salt (NaCl) will lower the freezing point of water. Make ice using salty water. Stick a thermometer in it to measure the temperature of the ice, it should be below 0C. Then put the solution in question in a beaker and place it among the crushed ice in a small bowl. Start the timer and see how long it takes for the solution to freeze. Frozen in this case would mean the solution would have solidified.

Answer 3

Salt lowers the freezing temparture of water. Make several solutions of salt water in increasin concentrations. Freeze them with a thermometer inside. Melting temperature is also the freezing point. the solution that begins to melt at 2C is "the one"

Answer 4

fp is lowered when you add solute into solvent.

when you add solute into a solvent, the fp is lowered because the solute interferes how the molecules of solvent are arranged.

Answer 5

Add the correct amount of alcohol.