Handling Experimental observations and data Essays

Handling Experimental observations and data Essays Handling Experimental observations and data Essay Handling Experimental observations and data Essay To determine the number of moles of water of crystallization in a hydrated salt, a small amount of the hydrated salt is taken, heated gently and then heated strongly to remove the water of crystallization. Procedure: 1. Take a clean and dry beaker and weigh it out accurately in an electronic balance. 2. Weigh out accurately 2.5 g of hydrated copper sulphate crystals in the crucible. : 3. Heat the contents of the crucible gently at first and then strongly. 4. Remove the crucible from the burner when all the water of crystallization is removed from the copper sulphate crystals. 5. Allow the contents of the crucible to cool down. 6. Weigh out the crucible with its contents again until a constant reading is obtained. Table of Results Substance to be Weighed Weight in Grams Beaker alone 50.00g Beaker + copper sulphate before heating 52.50g Beaker + copper sulphate after heating 51.44g Observation: * The beaker was not directly over the fire and the blue copper sulphate crystals at the bottom of the beaker begin to turn white. * In the space of about two minutes the blue colour of the copper sulphate crystals starts fading. * After time clumps of the substance is formed. * The substance is heated strongly and most of the crystals are decolourized to white now. * A minute or so passes and all of the copper sulphate crystals are completely white. Controlled Variables: 2.5g of hydrated copper sulphate Weight of beaker 50g Calculations Weight of hydrated copper sulphate + beaker before heating = 52.50g Weight of copper sulphate + beaker after heating = 51.44g Weight of water evaporated from hydrated copper sulphate = 52.5- 51.44 = 1.06g Weight of hydrated copper sulphate = 2.5g Weight of anhydrous copper sulphate = 2.5 1.06 = 1.44g R.M.M of water = (2à ¯Ã‚ ¿Ã‚ ½1) + 16 = 18 No. of moles of water evaporated = 1.06 à ¯Ã‚ ¿Ã‚ ½ 18 = 0.0589 = 0.06 moles 1 of mole of hydrated copper sulphate = 1 mole of anhydrous copper sulphate + ? moles of water No. of moles of water incorporated into 1.44g of anhydrous copper sulphate = 0.06 No. of moles of water incorporated into 1g of anhydrous copper sulphate = 0.06 à ¯Ã‚ ¿Ã‚ ½ 1.44 = 0.04g Mass of 1 mole of anhydrous copper sulphate = 63.5 + 32 + (4 à ¯Ã‚ ¿Ã‚ ½ 16) =159.5g No. of moles of water incorporated into 159.5g of anhydrous copper sulphate = 0.04 à ¯Ã‚ ¿Ã‚ ½ 159.5 = 6.38g Anomalous Result: Copper sulphate has five (5) moles of water but after heating I found it to have 6.38g. This was caused by experimental mistakes. Sources of Error I did not heat the substance gently properly. I let the spatula touch the substance. Ways to Improve Experimental Results I could improve my experimental result but fix the way I gentle heat the substance by waving it over the flame to make sure that all the water particles are evaporated out of the anhydrous copper sulphate. Conclusion The water crystallization in 2.5g of copper sulphate was evaporated by firstly being heated gently and then strongly.