Water of crystallization Aim:Prepare a standard solution of hydrated sodium borate to find the number of moles of water of crystallisation

Essay by achmedHigh School, 12th gradeA-, April 2005

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Safety spectacles

Weighing bottle

Balance capable of weighing to within 0.01g


Stirring rod with rubber end

Dropping pipette

Wash bottle of distilled water


Volumetric flask, 250 cm3

Beaker, 250 cm3

Retort stand

Burette clamp

Burette, 50cm3

Pipette, 25cm3

Pipette filler

Beaker, 100cm3

White tile

Conical flask, 250cm3

Reagents used:

Distilled Water

Hydrated Sodium Borate

1.0 M Hydrochloric acid

Screened methyl orange

Sodium Borate solution


Prepare a standard solution of hydrated sodium borate (250cm3 solution)

Place the weighing bottle on the balance and record the mass of the empty bottle.

Add approximately 4.80 grams of the hydrated sodium borate compound into the weighing bottle and record their weight together.

Transfer the measured hydrated sodium borate to the 250 cm3 beaker then find the mass of the weighing bottle once again to see how much of the compound was actually moved

Add small amounts of distilled water into the beaker while constantly stirring the water with the stirring rod and crushing the compound with the rubber end.

Repeat until compound is fully dissolved (make sure the solution does not rise over 250cm3)

Rinse the volumetric flask with distilled water then transfer the hydrated sodium borate solution into it. Make sure you rinse out the stirring rod, the beaker and the funnel with distilled water and pour this water into the volumetric flask to reduce chances of error (left behind solution).

Make the solution up to 250cm3. To do this make sure that when the bottom of the meniscus is nearing onto the mark at eye level, use the dropping pipette to make sure that you do not pass the mark.

Shake the volumetric flask several times (about eight times) by turning it all the way around and waiting for the solution to move downwards, then turning it back...