September 28, 2024, 06:25:20 AM
Forum Rules: Read This Before Posting


Topic: Freezing point chemistry help?  (Read 3606 times)

0 Members and 1 Guest are viewing this topic.

Offline THISMOMENTISFATE

  • Regular Member
  • ***
  • Posts: 33
  • Mole Snacks: +0/-1
Freezing point chemistry help?
« on: September 16, 2010, 08:24:35 AM »

the freezing point of ethanol (C2H5OH) is -114.6C. the molal freezing point depression constant for ethanol is 2.00C/m. what is the freezing point (C) of a solution prepared by dissolving 50.0 g of glycerin (C3H8O3, A nonelectrolyte) in 200 g of ethanol.

i tried to solve it on my own but im confused about the last part, this i what i have so far..

moles of glycerin= 50.0/92.10=0.54
molality=0.54/0.200=2.7


im a little confused about the numbers im supposed to use for the final answer...
final answer is -120.0 how do i get there?

Offline sjb

  • Global Moderator
  • Sr. Member
  • ***
  • Posts: 3653
  • Mole Snacks: +222/-42
  • Gender: Male
Re: Freezing point chemistry help?
« Reply #1 on: September 16, 2010, 08:27:10 AM »

the freezing point of ethanol (C2H5OH) is -114.6C. the molal freezing point depression constant for ethanol is 2.00C/m. what is the freezing point (C) of a solution prepared by dissolving 50.0 g of glycerin (C3H8O3, A nonelectrolyte) in 200 g of ethanol.

i tried to solve it on my own but im confused about the last part, this i what i have so far..

moles of glycerin= 50.0/92.10=0.54
molality=0.54/0.200=2.7


im a little confused about the numbers im supposed to use for the final answer...
final answer is -120.0 how do i get there?

If the freezing point depression is 2.0°C / m, and your concentration is 2.7 m ...?

Sponsored Links