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Both.okplease like for salt analysis we hav to test each fa2 like with naoh and nh3 or both or only one please helo
thanks a lot for the guide.God bless uAdvanced Practical Skills: Chemistry
(Booklet)
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this is like a perfect 9 pages booklet which teaches students how to perform practical. please share.
the booklet will be updated automatically on the same link. when a new version is uploaded the anouncement will be made on this thread. if there are any errors please report them.
if you want to add anything to this booklet or even modify it completely you are allowed to.
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man you are the real mvpI compiled a list of error and improvements for the last part of question 2 in physics paper 3. Only the first one you can use everywhere, as long as the question requires taking any type of measurement at all. These are all from the past papers marking schemes. These could be helpful if you're running out of time and had memorized these before, but please make sure these error and improvements fit the question!
1. Error: Two readings not enough to support the conclusion
Improvement: Take more sets of readings and plot a graph.
(This one works everywhere. Memorize this!)
2. Error: Large uncertainty in measured quantity because quantity is too small (like when measuring the thickness of an object)
Improvement: improved method to calculate this quantity like taking more readings at different parts of the object and dividing by number of readings for an average.
3. Error: Friction with surface (apply to any object that you have to pull on a surface)
Improvement: apply lubricant to surface
4. Error: (only when newton meter used horizontally!) Zero error on newton meter when used horizontally.
Improvement: adjust vertical arrangement of newton meter.
5. Error: (Keeping an object at certain height with your hands for a long time) keeping "object" at a certain height difficult
Improvement: use a clamp/tape.
ELECTRICITY:
6. Error: Voltmeter scale not sensitive enough/not precise enough
Improvement: Use a digital voltmeter/use a voltmeter that reads to 0.01 V.
7. Error: Wire not straight/wire kinked (coils) / difficulty in keeping wire straight
Improvement: Tape wire to a ruler/ clamp wire.
8. Error: Contact resistance/fluctuating ammeter or voltmeter readings
Improvement: Sand the crocodile clips to clean them/ tighten clips
OSCILLATIONS
9. Error: Difficult to judge start/center/ end of swing / complete swing
Improvement: use fiducial marks/pointer
10. Error: large uncertainty in time / time taken too short
Improvement: use video and timer that captures frame by frame video
11. Error: Object does not travel in a straight line
Improvement: Method of guiding object to travel in a straight line
-------------------------------------------------------------------------------------------------------------
12: Error: (when measuring degrees in an experiment that's suspended in the air like the degrees between a rubber band when stretched) difficult to hold protractor steady
Improvement: project image of the rubber band onto a screen.
13: Error: applying a force on the object when releasing it
Improvement: use an electromagnet to release the object so it falls/moves on a slope or surface under the force of its own weight.
I posted a link of this post to the main page so it is accessible easily. would you mind if I paste this content on the first page giving you the credit?I compiled a list of error and improvements for the last part of question 2 in physics paper 3. Only the first one you can use everywhere, as long as the question requires taking any type of measurement at all. These are all from the past papers marking schemes. These could be helpful if you're running out of time and had memorized these before, but please make sure these error and improvements fit the question!
1. Error: Two readings not enough to support the conclusion
Improvement: Take more sets of readings and plot a graph.
(This one works everywhere. Memorize this!)
2. Error: Large uncertainty in measured quantity because quantity is too small (like when measuring the thickness of an object)
Improvement: improved method to calculate this quantity like taking more readings at different parts of the object and dividing by number of readings for an average.
3. Error: Friction with surface (apply to any object that you have to pull on a surface)
Improvement: apply lubricant to surface
4. Error: (only when newton meter used horizontally!) Zero error on newton meter when used horizontally.
Improvement: adjust vertical arrangement of newton meter.
5. Error: (Keeping an object at certain height with your hands for a long time) keeping "object" at a certain height difficult
Improvement: use a clamp/tape.
ELECTRICITY:
6. Error: Voltmeter scale not sensitive enough/not precise enough
Improvement: Use a digital voltmeter/use a voltmeter that reads to 0.01 V.
7. Error: Wire not straight/wire kinked (coils) / difficulty in keeping wire straight
Improvement: Tape wire to a ruler/ clamp wire.
8. Error: Contact resistance/fluctuating ammeter or voltmeter readings
Improvement: Sand the crocodile clips to clean them/ tighten clips
OSCILLATIONS
9. Error: Difficult to judge start/center/ end of swing / complete swing
Improvement: use fiducial marks/pointer
10. Error: large uncertainty in time / time taken too short
Improvement: use video and timer that captures frame by frame video
11. Error: Object does not travel in a straight line
Improvement: Method of guiding object to travel in a straight line
-------------------------------------------------------------------------------------------------------------
12: Error: (when measuring degrees in an experiment that's suspended in the air like the degrees between a rubber band when stretched) difficult to hold protractor steady
Improvement: project image of the rubber band onto a screen.
13: Error: applying a force on the object when releasing it
Improvement: use an electromagnet to release the object so it falls/moves on a slope or surface under the force of its own weight.
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