2020-2021 AS LEVEL CHEMISTRY
PRACTICALS (1 to 9)
Edexcel International A level
, CORE PRACTICAL 1 – MEASUREMENT OF THE MOLAR VOLUME OF A GAS
1. Place 30 cm3 of 1 mol dm-3 ethanoic acid (CORROSIVE) in the boiling tube
2. Place approximately 0.05 g of calcium carbonate in a test tube
3. Weigh the test tube and its contents accurately
4. Remove the bung from the boiling tube and tip the calcium carbonate into the boiling tube. Quickly
replace the bung in the boiling tube – major source of error as gas escapes → place solid into a
container attached with a thread & knock it over / attach marble chips on a string to the bung, seal
the boiling tube with bung & then tip the boiling tube so the acid reacts with marble chip
5. Once the reaction is over (wait until no effervescence), measure the volume of gas collected in the
measuring cylinder – only this method if gas is not soluble in water / CO2 IS SLIGHTLY SOLUBLE IN
WATER SO NOT EXACT VOLUME
6. Reweigh the test tube that had contained the calcium carbonate
7. Repeat the experiment six more times, increasing the mass of calcium carbonate by about 0.05 g
each time. Do not exceed 0.40 g of calcium carbonate – avoid producing more gas than the
measuring cylinder can fit
8. Plot a graph of mass of CaCO3 in g (x-axis) against volume of CO2 in cm3 (y-axis) & line of best fit
Chemical reaction between CaCO3 & CH3COOH:
CaCO3 + 2CH3COOH → Ca(CH3COO)2 + CO2 + H2O
How to accurately find the mass of CaCO3 by weighing:
1. Weigh test tube containing CaCO3
2. Reweigh the test tube after CaCO3 has been tipped out
3. Loss on transfer – allows for the mass of any CaCO3 that remains in the test tube after tipping it out
Three things to ensure that metal oxides/carbonates (etc.) are compared fairly:
1. Same amount / moles / mass of solid/metal oxide-carbonate
2. All powders
3. Same concentration of acid
4. Same temperature
5. Same time to replace bung
The molar volume of any gas at a given conditions of pressure & temperature is the same – Avogadro’s law
Copyright © 2020–2021 – All Rights Reserved.
PRACTICALS (1 to 9)
Edexcel International A level
, CORE PRACTICAL 1 – MEASUREMENT OF THE MOLAR VOLUME OF A GAS
1. Place 30 cm3 of 1 mol dm-3 ethanoic acid (CORROSIVE) in the boiling tube
2. Place approximately 0.05 g of calcium carbonate in a test tube
3. Weigh the test tube and its contents accurately
4. Remove the bung from the boiling tube and tip the calcium carbonate into the boiling tube. Quickly
replace the bung in the boiling tube – major source of error as gas escapes → place solid into a
container attached with a thread & knock it over / attach marble chips on a string to the bung, seal
the boiling tube with bung & then tip the boiling tube so the acid reacts with marble chip
5. Once the reaction is over (wait until no effervescence), measure the volume of gas collected in the
measuring cylinder – only this method if gas is not soluble in water / CO2 IS SLIGHTLY SOLUBLE IN
WATER SO NOT EXACT VOLUME
6. Reweigh the test tube that had contained the calcium carbonate
7. Repeat the experiment six more times, increasing the mass of calcium carbonate by about 0.05 g
each time. Do not exceed 0.40 g of calcium carbonate – avoid producing more gas than the
measuring cylinder can fit
8. Plot a graph of mass of CaCO3 in g (x-axis) against volume of CO2 in cm3 (y-axis) & line of best fit
Chemical reaction between CaCO3 & CH3COOH:
CaCO3 + 2CH3COOH → Ca(CH3COO)2 + CO2 + H2O
How to accurately find the mass of CaCO3 by weighing:
1. Weigh test tube containing CaCO3
2. Reweigh the test tube after CaCO3 has been tipped out
3. Loss on transfer – allows for the mass of any CaCO3 that remains in the test tube after tipping it out
Three things to ensure that metal oxides/carbonates (etc.) are compared fairly:
1. Same amount / moles / mass of solid/metal oxide-carbonate
2. All powders
3. Same concentration of acid
4. Same temperature
5. Same time to replace bung
The molar volume of any gas at a given conditions of pressure & temperature is the same – Avogadro’s law
Copyright © 2020–2021 – All Rights Reserved.
