Chemistry practical: 1

Question 1

Main goal of this practical

Answer 1

Measure the molar volume of gas

Question 2

Step 1

Answer 2

Place 30cm3 of ethanoic acid in a boiling tube

Question 3

Step 2

Answer 3

Set up apparatus, with a bung attached to boiling tube into the upturned cylinder with water

Question 4

Step 3

Answer 4

Place around 0.05g of calcium carbonate in weighing bottle and weigh the test tube + contents

Question 5

Step 4

Answer 5

Quickly remove bung and place into tube with ethanoic acid then put back

Question 6

Why does the bung need to be replaced quickly?

Answer 6

To prevent gas loss so volume of gas can be accurately recorded

Question 7

Step 5

Answer 7

Once reaction is over, measure volume of gas collected in measuring cylinder

Question 8

Step 6

Answer 8

Reweigh empty weighing bottle
Then take away previous measurement

Question 9

Why is weighing by mass done?

Answer 9

To ensure any calcium carbonate not added to boiling tube is accounted for

Question 10

Step 7

Answer 10

Repeat experiment by adding 0.05g more but do not exceed 0.4g

Question 11

Why is there a limit on the mass of calcium carbonate added?

Answer 11

Because this will produce a lot of gas which will exceed the volume capacity in the measuring cylinder

Question 12

Main problem of this experiment

Answer 12

Gas will escape when bung is being replaced

Question 13

How can the main problem be overcome?

Answer 13

Include the calcium carbonate inside the vessel which can be added to acid by tipping rather than having to remove bung

Question 14

Why don’t we use a strong acid?

Answer 14

Because this will mean a faster reaction, thus more gas released quicker. So more gas released when the bung is removed

Question 15

If a gas syringe is used, what problem may happen and how do w fix it?

Answer 15

The plunger isn’t free moving so a lubricant is required

Question 16

CO2 and water problem

Answer 16

CO2 is slightly soluble in water therefore not all gas will be accurately measured