Core Practical 1: Measure the molar volume of a gas

Question 1

ethanoic acid will

Answer 1

sting if gets into cuts in the skin

Question 2

the setup for the experiment is:

Answer 2

• connect a delivery tube to the boiling tube containing the reactants with a bung
• the delivery tube output should be in a 100cm3 measuring cylinder inverted in a water bath
• the cylinder can be clamped for ease

Question 3

the method is:

Answer 3

• measure 30cm3 of 1 mol dm-3 ethanoic acid and pout in the boiling tube
• weigh 0.5g of calcium carbonate and weigh in a test tube, recording the mass
• remove the bung from the boiling tube and add the CaCO3, replacing the bung quickly
• reweigh the empty test tube to obtain mass of CaCO3
• when reaction over, record volume of CO2 gas collected

-repeat the reaction but increase the mass of CaCO3 by 0.05g each time up to 0.40g in one go

Question 4

the equation for the reaction is:

Answer 4

2CH3COOH + CaCO3 → Ca(CH3COO)2 + CO2 + H2O

Question 5

what is the major source of error and how can you eradicate this?

Answer 5

• replacing the bung too slowly allows gas to escape

- Use tube containing the acid inside the vessel containing the calcium carbonate – tip to mix the reagent.