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Moles Determination - Coggle Diagram
Moles Determination
Determination of the Relative Atomic Mass of Magnesium
Method 2
Rinse the conical flask with some distilled water and add the washings to the evaporating basin
Evaporate the solution until a dry solid is left in the evaporating basin
Pour the solution produced into the evaporating basin
Leave to cool then reweigh the evaporating basin containing solid magnesium sulphate
Weigh a clean evaporating basin
Errors
Similar to determination of copper carbonate
Solid magnesium sulphate may not be completely dry
To ensure complete dryness heat until the mass no longer changes
Method 1
Weigh 0.15g of magnesium, adding it to the acid, placing the bung into the flask immediately
Record the final volume of hydrogen in the measuring cylinder
Add 10cm^3 of sulfuric acid to the conical flask
Retain the solution in the conical flask for method 2
Set the apparatus up as before
Safety
Sulfuric acid - causes severe skin burns and eye damage
Determination of the Composition of Copper (||) Carbonate
Errors
Some copper carbonate may not react
Swirl the conical flask to mix the contents and ensure that the reaction goes to completion
Carbon dioxide may dissolve in the water
Use a gas syringe to measure the volume of CO2 instead
Some carbon dioxide may escape before the bung is inserted
Insert the bung as soon as the acid has been poured into the conical flask
Some copper carbonate may remaind in the weighing boat so it's not tranferred to the conical flask
Use the weighing by difference technique
Weigh the boat with the copper carbonate, add the copper carbonate to the conical flask then reweigh the empty boat - the difference between the masses is the exact mass of copper carbonate
Safety
CuCO3.Cu(OH)2 - causes serious eye irritation; harmful if swallowed or inhaled
Sulfuric acid - causes severe skin burns and eye damage
Method
Measure 50cm^3 of H2SO4 in a 50cm^3 measuring cylinder
Add the H2SO4 into the conical flask and immediately insert the stopper (the gas will collect in the measuring cylinder)
Weigh 1.5g of CuCO3.Cu(OH)2 and add it to the conical flask
Record the final volume of carbon dioxide in the measuring cylinder
Set up the apparatus using a 100cm^3 measuring cylinder and a 250cm^3 conical flask