Your SlideShare is downloading. ×
0
A2 /EXPT/THER/KELLY/APRIL
A2 /EXPT/THER/KELLY/APRIL
A2 /EXPT/THER/KELLY/APRIL
A2 /EXPT/THER/KELLY/APRIL
A2 /EXPT/THER/KELLY/APRIL
A2 /EXPT/THER/KELLY/APRIL
A2 /EXPT/THER/KELLY/APRIL
A2 /EXPT/THER/KELLY/APRIL
A2 /EXPT/THER/KELLY/APRIL
A2 /EXPT/THER/KELLY/APRIL
Upcoming SlideShare
Loading in...5
×

Thanks for flagging this SlideShare!

Oops! An error has occurred.

×
Saving this for later? Get the SlideShare app to save on your phone or tablet. Read anywhere, anytime – even offline.
Text the download link to your phone
Standard text messaging rates apply

A2 /EXPT/THER/KELLY/APRIL

193

Published on

Published in: Business, Technology
0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total Views
193
On Slideshare
0
From Embeds
0
Number of Embeds
0
Actions
Shares
0
Downloads
1
Comments
0
Likes
0
Embeds 0
No embeds

Report content
Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
No notes for slide

Transcript

  • 1. Electric Method – Specific Latent Heat of Vaporisation of water by April and Kelly Oct, 10th
  • 2. Steps – Part 1
    • Add some water into a beaker to about three quarters full.
    • Heat the beaker of water to its boiling point using a spirit burner. Then stop heating.
  • 3. Steps – Part 2
    • Place the beaker in a calorimeter to prevent heat entering to leaving. Leave a hole at the top to let steam out.
    • Weigh it using an electronic balance. Note down the mass m1.
  • 4. Steps –Part 3
    • Set up the electrical circuit as shown. Emerge the 50Ω resistance in the beaker of water.
  • 5.
    • Switch on and at the same time start the stopwatch. Note down the readings of the voltmeter and ammeter.
    Steps –Part 4
  • 6. Steps –Part 5
    • After some time when at least half of the water has vaporised, switch off and note down the time t of the current flowing.
    • Weigh the beaker, calorimeter and water again. Note down the mass m2.
  • 7. Tabulation and Calculation
    • m is the mass of vaporised water.
    • Q is the heat supplied to the boiling water.
    • Formula: L= Q/m =VIt/ m 2-m1.
    m=m 2-m1/g m 2/g m 1/g Q=VIt /J t/s I/A V/V
  • 8. Sources of Errors
    • The weighing of the beaker of water after being heated to its boiling point may take some time and cool the water a bit.
    • The electrical resistance is much colder than boiling water and when emerged in it, it will absorb some heat.
    • During the electrical heating, water vapour may liquefy again touching the cold lid of the calorimeter and drop back into the beaker.
  • 9. Improvements
    • Weigh the beaker of water quickly when it’s hot.
    • Switch on the circuit before the resistance is emerged in water for some time to heat it up. Try to use a small electrical resistance.
    • Heat the calorimeter lid for a while (no touching) before it is used.
  • 10. Safety Precautions
    • Take care not to split any drops when moving hot water.
    • Be careful about the fire of the spirit burner.
    • Pay attention not to split water on wires and power supply.

×