March 04, 2021, 10:29:28 AM
Forum Rules: Read This Before Posting


Topic: Intermolecular Force  (Read 2835 times)

0 Members and 1 Guest are viewing this topic.

Offline ILoveISO

  • Full Member
  • ****
  • Posts: 101
  • Mole Snacks: +2/-13
Intermolecular Force
« on: February 07, 2010, 02:34:53 AM »
Calculate the total heat needed to convert 1.00 g of ice at -5.00 oC to water vapor at 105 oC.
Specific heat of liquid water = 4.184 J/(g oC), specific heat of solid water = 2.06 J/(g oC),
specific heat of water vapor = 1.84 J/(g oC), ΔHfusion = 6.02 kJ/mol, ΔHvap = 40.7 kJ/mol.

How come q5 = Cvapor ⋅ m ⋅ ΔT = 1.84 J/(g oC) × 1.00 g × 5.00 oC = 9.20 J

Why is it multiplied by 5 degree C? and
q3 = Cwater ⋅ m ⋅ ΔT = 4.184 J/(g oC) × 1.00 g × 100. oC = 418 J

Why is that 100 degree C?

Offline Borek

  • Mr. pH
  • Administrator
  • Deity Member
  • *
  • Posts: 26310
  • Mole Snacks: +1711/-402
  • Gender: Male
  • I am known to be occasionally wrong.
    • Chembuddy
Re: Intermolecular Force
« Reply #1 on: February 07, 2010, 04:50:36 AM »
What is boiling point of water?
ChemBuddy chemical calculators - stoichiometry, pH, concentration, buffer preparation, titrations.info, pH-meter.info

Offline ILoveISO

  • Full Member
  • ****
  • Posts: 101
  • Mole Snacks: +2/-13
Re: Intermolecular Force
« Reply #2 on: February 07, 2010, 05:32:34 PM »
Why is the vapor one multiplied by 5 degrees

Offline Borek

  • Mr. pH
  • Administrator
  • Deity Member
  • *
  • Posts: 26310
  • Mole Snacks: +1711/-402
  • Gender: Male
  • I am known to be occasionally wrong.
    • Chembuddy
Re: Intermolecular Force
« Reply #3 on: February 07, 2010, 06:18:03 PM »
Think what changes must ice come through before it becomes steam at 105 deg C.
ChemBuddy chemical calculators - stoichiometry, pH, concentration, buffer preparation, titrations.info, pH-meter.info

Offline ILoveISO

  • Full Member
  • ****
  • Posts: 101
  • Mole Snacks: +2/-13
Re: Intermolecular Force
« Reply #4 on: February 07, 2010, 07:35:22 PM »
Wouldn't it have to go thru 100 degree C before it boils? Don't get why is it multipled by only 5 degrees wouldn't it need another 100?

Offline Borek

  • Mr. pH
  • Administrator
  • Deity Member
  • *
  • Posts: 26310
  • Mole Snacks: +1711/-402
  • Gender: Male
  • I am known to be occasionally wrong.
    • Chembuddy
Re: Intermolecular Force
« Reply #5 on: February 08, 2010, 03:39:26 AM »
Steam already has temperature of 100 deg C, so it has to be heated by 5 deg C only. Water was already heated to 100 deg C earlier.
ChemBuddy chemical calculators - stoichiometry, pH, concentration, buffer preparation, titrations.info, pH-meter.info

Sponsored Links