Experiments

Question 1

Waters of crystallisation method

Answer 1

1) Weigh an empty crucible
2) Add the hydrated salt into the weighted crucible
3) Weigh the crucible and the hydrated salt
4) Using a pipe clay triangle, support the crucible containing the hydrated salt on a tripod
5) Heat the crucible and contents gently for around one minute then heat it strongly for a further 3 minutes
6) Leave the crucible to cool
7) Weigh the crucible and hydrous salt

Question 2

Making a standard solution

Answer 2

1) Accurately measure the mass of the solid using a balance to an appropriate number of decimal places
2) Dissolve the solid carefully in about 100cm3 of distilled water, stirring with a glass rod
3) Transfer the solution to a clean 250cm3 volumetric flask, using a funnel
4) Rinse the beaker, glass rod and funnel with distilled water and include the rinsing in the volumetric flask
5) Make up to just below the mark with distilled water
6) Make up the solution tot he mark so that the bottom of the meniscus lines up perfectly with the mark, using a dropping pipette
7) Insert the stopper, and invert slowly several times to mix thoroughly