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Chemistry ATP Analysis by
Vasumitra Gajbhiye
How to check if a liquid is water?
Check boiling point = 100 or melting point = 0
Why it is important to immediately put a bung in the conical flask in an experiment
where gas is produced?
minimize gas loss/ escape before bung is replaced
State the advantage of measuring the volume of gas collected every 10 seconds
rather than every 20 seconds
more points / data so
better / smoother graph / curve / line
Why condensers are used?
To cool the vapour. So that the gas condense into a liquid
Which flask is used in distillation?
Distillation/ round bottom flask
How to keep the temperature of a apparatus constant?
Use water bath
How to prevent escape of gas when magnesium is added to sulfuric acid?
partitioned container, suspend magnesium on thread,
If colour of litmus paper is red what is the pH?
1
Why the flask is rinsed with distilled water?
Chemistry ATP Analysis by Vasumitra Gajbhiye 1
, clean it.
remove residue and impurities from previous experiments
What are some errors and improvements in titration experiment?
errors
any two from:
• using measuring cylinder
• missing endpoint / misjudging colour change
• not repeating
improvements
any two from:
• use pipette (in place of measuring cylinder)
• add more slowly
• repeat (and find mean)
Why would carrying out the experiment in a polystyrene cup rather than a boiling
tube
improve the accuracy of the results?
Better insulator so reduce heat loss even more
What is advantage of measuring cylinder?
convenient / easy / quick to use;
What is disadvantage of measuring cylinder?
Inaccurate measurement.
Why should we warm solution containing sodium hydroxide carefully?
sodium hydroxide is hazardous / irritant / caustic;
boiling causes mixture to spit / blow-out;
What will happen if a gas continues to enter a closed conical flask with a liquid
inside it?
Liquid will be pushed out of flask.
Suggest why the experiments were done in a polystyrene cup rather than a glass
beaker.
Polystyrene cup is a insulator, so reduce heat loss.
Chemistry ATP Analysis by Vasumitra Gajbhiye 2
Chemistry ATP Analysis by
Vasumitra Gajbhiye
How to check if a liquid is water?
Check boiling point = 100 or melting point = 0
Why it is important to immediately put a bung in the conical flask in an experiment
where gas is produced?
minimize gas loss/ escape before bung is replaced
State the advantage of measuring the volume of gas collected every 10 seconds
rather than every 20 seconds
more points / data so
better / smoother graph / curve / line
Why condensers are used?
To cool the vapour. So that the gas condense into a liquid
Which flask is used in distillation?
Distillation/ round bottom flask
How to keep the temperature of a apparatus constant?
Use water bath
How to prevent escape of gas when magnesium is added to sulfuric acid?
partitioned container, suspend magnesium on thread,
If colour of litmus paper is red what is the pH?
1
Why the flask is rinsed with distilled water?
Chemistry ATP Analysis by Vasumitra Gajbhiye 1
, clean it.
remove residue and impurities from previous experiments
What are some errors and improvements in titration experiment?
errors
any two from:
• using measuring cylinder
• missing endpoint / misjudging colour change
• not repeating
improvements
any two from:
• use pipette (in place of measuring cylinder)
• add more slowly
• repeat (and find mean)
Why would carrying out the experiment in a polystyrene cup rather than a boiling
tube
improve the accuracy of the results?
Better insulator so reduce heat loss even more
What is advantage of measuring cylinder?
convenient / easy / quick to use;
What is disadvantage of measuring cylinder?
Inaccurate measurement.
Why should we warm solution containing sodium hydroxide carefully?
sodium hydroxide is hazardous / irritant / caustic;
boiling causes mixture to spit / blow-out;
What will happen if a gas continues to enter a closed conical flask with a liquid
inside it?
Liquid will be pushed out of flask.
Suggest why the experiments were done in a polystyrene cup rather than a glass
beaker.
Polystyrene cup is a insulator, so reduce heat loss.
Chemistry ATP Analysis by Vasumitra Gajbhiye 2
