Practicals Flashcards
How do you make a volumetric solution?
Record a precise mass of the solid,
Add 100cm3 distilled water and stir until dissolved,
Pour into volumetric flask, rinse beaker and stirring rod into flask also,
Make up to 250cm3.
Which practical do you have to extrapolate backwards?
Measurement of an enthalpy change.
How do you test for hydroxide ions in aqueous solution?
Litmus paper.
How do you test for alkaline gas (ammonia)?
Damped blue litmus paperand place at tip of NH3 bottle.
How do you test for carbonate ions?
Add HCl to equal volume of Na2CO3. Transfer gas into boiling tube containing CaOH and shake using a stopper.
How do you test for sulfate ions?
Add dilute HCl and then an equal volume of BaCl.
How do you test for chloride ions in solid potassium halides?
Add KCl to H2SO4 and test gas with blue litmus paper.
How do you test for bromide ions in solid potassium halides.
Add H2SO4 and test gas with K2C2O7 soaked onto filter paper.
how do you test for iodide ions in solid potassium halides.
Add H2SO4 and test with lead nitrate solution soaked onto filter paper.
How do you carry out distillation?
Measure out the acidified potassium dichromate. Cool. Add ethanol drop wise and shake. Add anti-bumping granules. Heat gently until 5cm3 of liquid is distilled off into a test tube immersed in a beaker of cold water.
How do you test for an alcohol?
Add metallic sodium
What is the continuous monitoring method?
Use a gas syringe or a trough to record the volume of hydrogen gas produced every 15 seconds for 2 and a half minutes.
What is the initial rate method?
Mix H2SO4, distilled water and starch solution.
Use a burette to add KI.
Add sodium thiosulfate.
Stir and add hydrogen peroxide, stop timer when mixture turns blue/black.
What do you use to calibrate a pH probe?
Standardised buffers of 4, 7 and 9.
Plot a graph of buffer pH against recorded pH.
How do you prepare a pure organic solid?
Warm solution but do not exceed the temperature of decomposition. the allow to cool to precipitate the solid. Filter under reduced pressure to allow the air to travel through the sample and not just around it.
