I had to perform an experiment for the freezing point depression in which we had to determine the freezing points of water as a pure solvent, sodium chloride, sucrose, and ethylene glycol.

Question

We had to work with a partner so I completed the experiment for water, NaCl, and the glycol and had to get the info for sucrose from my partner. The data that was collected was the freezing pint of DI water which was the corrected value for the thermometer that I used. We had to record the temp every 30 seconds until we saw ice crystals. We had to do the same thing for the NaCl, sucrose, and gycol. For the NaCl we started at 0.5 min in which the temp was 15.0 degrees celsius and crystals formed at 10.5 min at -2.0 degrees celsius.

We had to measure out 5.800g of NaCl and record the exact weight. First I weighed the measuring boat and then I poured in the NaCl so to get the exact weight I subtracted the mass of the measuring boat with NaCl from the mass of just the boat. Is this correct?

Also, I need to calculate the # of moles of solute for NaCl and sucrose. To do this for NaCl would I divide the mass of solute by the molecular weight of NaCl?

Answer 1

mass boat + NaCl - mass boat = mass NaCl
moles NaCl = grams/molar mass.

Answer 2

ok thank you!!!