schmied/reid©2007
Boiling Water Lab Directions
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PURPOSE:
• Perform and Observe safe lab practices.
• Identify differences by physical properties ( boiling point of fresh water vs unknown solution).
• Practice identifying thermometer errors and correcting for these.
MATERIALS:
Terrill burner
ring and stand
ceramic wire guaze pad
universal clamp
600ml beaker
4 boiling chips
#4 single hole rubber stopper
-20 - 150 ûC thermometer
100ml graduated cylinder
goggles
beaker tongs
clock
aprons
matches
match cup
part 1 (400 ml fresh water)
part 2 (400 ml unknown liquid)
PROCEDURE:
1. Get draft Data table One and/or Two ready. Use pencil ( You will do CQC ones later)
2. Go to lab station and inventory all your materials. Get missing equipment.
Take the 600ml beaker OFF the wire guaze pad and put it on the station top. Turn thermometer to side so the flame isn't under it.
3. Move your T burner out from under the lab set up. Light off and adjust Terrill burner Now slide T burner under guaze pad and quickly adjust the ring on the stand so the tip of the blue cone is just touching the bottom of the wire guaze pad. IF it ISN'T tell your instructor. NOW move Terrill burner aside andTurn off.
4a. (FW run) Use a 100ml GC to fill the 600ml beaker with 400 mls of pure water. Place beaker on the ring stand. Be careful. the ring and wire guaze pad may be hot.
4b. (UNK run) Use a 100ml GC to fill the 600ml beaker to 400ml if needed. Be careful. the ring and wire guaze pad may be hot.
5. Lower the universal clamp/stopper/thermometer assembly so the bottom of the thermometer is about at the 150ml mark of the beaker.
6. Place four boiling chips in the 600ml beaker. Be sure you keep them out of the sink!
7. Re light Terrill burner. Keep aside, away from apparatus. Get team ready to take data.
8. Take four 30 second temperature readings without terrill burner. Enter data on your Data Table.
9. After the fourth reading, slide Terrill burner under gauze pad/beaker (Keep it there).
10. Take 30 sec. temperature readings until boiling and you record 4 readings within 0.2ûC.
11. Turn off Terrill burner. Carefully pour out water (DT1). Put Boiling chips back in beaker, or cool unknown solution (DT2) in cooling bucket. Reset lab and clean area.
12. Determine Thermometer error by comparing average boiling temp to 100ûC (actual boiling point of Fresh water). If the therm read high you must subtract to correct error, if low, you must add. Now correct all your readings based upon this error.
13. Homework will vary. Basically PreLab Q's 1-7 and 19 & 20 are first, then 8-11 and the first part of 13, the last do is to complete the Lab Questions. If a Figure assigned, ensure your Figure is complete with all equipment shown and properly labelled.
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