To make a standard solution
1) 2.4g to 2.5g of sulphamic acid was weighed out, firstly by weighing the container and the sulphamic acid together, then pouring the sulphamic acid into a beaker. The container was then weighed again and the initial weight and the weight of the container alone were subtracted from one another to provide the mass of the sulphamic acid. 2) The sulphamic acid was then dissolved in 50cm³ of distilled water, using a glass rod to ensure it is completely dissolved. 3) Using a funnel, we poured the solution into the 250cm³ volumetric flask, ensuring the beaker, glass rod and funnel were cleaned with distilled water into the volumetric flask to provide that all of the sulphamic acid in the solution was in the volumetric flask. 4) We filled the volumetric flask with distilled water up to the 250cm³ mark, making sure that the bottom of the meniscus is on the line. 5) We stoppered the flask and inverted it several times to certify that the solution was well mixed. 6) We then labelled the volumetric flask with its contents and its concentration.
| Mass in grams
Container and acid
Mass of NH₂SO₃H = 97.09
Volume = 250cm³÷1000=0.25dm³
Moles = mass ÷ RMM ∴ 2.52÷97.09 = 0.0260mol
Concentration = mass ÷ volume ∴ 0.026÷ 0.25 = 0.104moldm¯³ Errors:
The amount of sulphamic acid we added to the beaker was 0.02g heavier than what was required, which was 2.4g to 2.5g.
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