Extracts from this document...

Introduction

Raghav Ramabadran 15 October 2007 SCH3U7-02 Grade 11 IB Chemistry Mr. Laratt Smith Lab 1: Determining the Water of Crystallisations Purpose: The purpose of this lab is to determine the number of moles of water of crystallisations in crystals of a white hydrated salt which is called Zinc (II) Sulfate (ZnSO4) by heating it to constant mass in a crucible. Also this lab will determine the formula and the name for the hydrated salt. Materials: * A small crucible with lid * A pipe clay triangle * A Bunsen burner * A tool that emits flames (a lighter for example) * A Scupula, tong, and the retort stand * A weighing machine that shows the mass in grams (g) * A pair of goggles * A cookie sheet Procedure: 1) Wear your goggles, and weigh the empty crucible with its lid on the weighing machine, and record the results as accurately as possible. 2) Take the scupula and fill the crucible one-third (1/3rd) full of the Zinc (II) Sulfate (ZnSO4) crystals. Replace the lid and reweigh the crucible, and record the results. 3) Place the crucible with the lid on the retort stand. ...read more.

Middle

Sulfate (ZnSO4) after 4th heating 17.27g There is none because I used a digital device to determine the mass, so I can't have possibly made any mistakes. Mass given by weighing machine in grams (g) � 0.005g *Percent of Uncertainty = (absolute uncertainty) � actual weight) � 100 {0.005g (absolute uncertainty) � 17.27g (actual weight)} � 100 = 0.029% Percent of Uncertainty = 17.27g � 0.029% Determining the Number of moles of Water of Crystallisation and Hydrate formula of Zinc (II) Sulfate (ZnSO4): Conclusion: In conclusion, to find out the hydrate formula of any salt, the salt has to be heated until there is no further weight loss. This is so because when determining the hydrate formula, you have to find the total mass of the hydrated salt in the crucible with the lid, the total mass of the salt in the crucible with the lid after it has been heated until no further weight loss, the mass of the crucible with lid, and the mass of the dehydrated salt. These masses has to be the 4 variables used to determine the hydrate formula, because if there is no further weight loss then all the water in the hydrated salt has been evaporated. ...read more.

Conclusion

Sulfate Heptahydrate (ZnSO4�7H2O). I believe that the solution for this problem is to analyze the data more clearly and then do the lab. The next problem was that in the calculations if I didn't round the moles, my answer for the hydrate ratio would have been 6.85:1 for hydrate to Zinc (II) Sulfate (ZnSO4). I presume that if I was given an additional 15-20 minutes for an extra heating, I could of gotten exactly 7 as my hydrate without the rounding of both the moles of water lost (H2O lost), and the rounding of the moles of the dehydrated Zinc(II) Sulfate (ZnSO4). All in all this lab is like a precursor to the creation of amazing future labs, and by learning to identify the different ways you can make mistakes in a lab, the future labs will be better than the rest. A picture of a plate full of Zinc (II) Sulfate (ZnSO4) salts. It is a colorless crystalline, water soluble chemical compound. http://img.alibaba.com/photo/50343956/Zinc_Sulfate.jpg A picture of Zinc (II) Sulfate Heptahydrate (ZnSO4�7H2O), which is also called the mineral goslarite (also known as the white vitrol). It is transparent to translucent and ranges from colorless, green, blue, or brown. It forms acicular crystals, stalactitic forms and massive clumps. http://www.epsilonfert.com/showcase/images/Zinc_Sulphate_Heptahydrate.jpg ...read more.

This student written piece of work is one of many that can be found in our International Baccalaureate Chemistry section.