An experiment to obtain Zinc Oxide from Calamine Research Zinc has the symbol Zn. It is a bluish-white metallic element that has many industrial applications. Zinc is one of the transition elements of the periodic table. The atomic number of zinc is 30. The ores of zinc have long been known, but zinc was not recognised as a separate element until 1746, when the German chemist Andreas Sigismund Marggraf isolated the pure metal by heating calamine and charcoal.
Uses: The metal is used predominantly as a protective coating, or galvaniser, for iron and steel; as an ingredient of various alloys, especially brass; as plates for dry electric cells, and for die-castings. Zinc oxide, known as Zinc white or Chinese white, is used as a paint pigment. It is also used as a filler in rubber tires and is employed in medicine as an antiseptic ointment. Decomposition: In chemistry, decomposition is the breaking down of a substance or compound, through a chemical reaction, into its simpler components. Such reduction may yield either elements or compounds as products.
A common agent of decomposition in chemistry is heat, which can reduce both inorganic and organic compounds to their constituents. Water, for example, decomposes into hydrogen and oxygen when exposed to an electric current. Also, chemical action, as by the use of acids or alkalis and as accelerated by catalysis, is used in laboratories to reduce compounds. Introduction I am going to carry out an experiment, which involves the heating up of Calamine and weighing it at different intervals. Calamine is a mineral containing Zinc Carbonate (ZnCO3).
On heating a reaction takes places enabling the Zinc Carbonate to decompose as follows: Zinc Carbonate Zinc Oxide + Carbon Dioxide ZnCO3 ZnO + CO2 This equation helps us to do theoretical conversions of Calamine into Zinc oxide. This would be fine however the accuracy of this is unknown. Thus, it must be investigated. To do this, I will need to produce a conversion table showing the amount of Zinc oxide made by experimenting from heating up different masses of Zinc Carbonate. Another chart must also be produced showing the theoretical values (using the above equation) as well as the actual amounts.
-2- Jack Mariner Chemistry Coursework Hypothesis My prediction for this experiment is that as the amount of Calamine used increases, the Zinc Oxide produced from this will also increase proportionally. The results should lead to a straight-line graph with a positively strong correlation. Here is a straight line graph demonstrating my hypothesis: I don’t actually think that my results will lead to a perfect correlation like shown above. I predict for anomalous results to occur leading to strong correlation not perfect. The reason for this prediction is because of the theoretical amounts as follows.
To perform the experiment, the following apparatus must be used: Bunsen burner, Test tubes, Tongs, Mineral wool, Calamine, Safety goggles, Heatproof mat, Electronic Scales. The apparatus should be set up like this: The Bunsen burner will be used for the heating up of the calamine. The test tubes (or other similar boiling tubes) will be needed to hold all the contents in them. The tongs will be needed for safety- if the test tubes -5- Jack Mariner Chemistry Coursework have heat applied to them, they will get hotter and will therefore burn our hands. Basically they are used to hold the test tubes safely.
The mineral wool is put in the top of the test tube, like a plug, to prevent solids from escaping, whilst allowing Carbon dioxide to escape. Normal wool must not be used because it would burn a lot easier and could catch on fire. Calamine must be used for the experiment to work. The goggles must be worn for protection and the heatproof mat used likewise. The electronic Scales are used for accurate measurements. Safety Precautions Although this experiment is very simple, safety must always be taken into account. Firstly, heat is being applied so you must lay a heatproof mat out protecting the surface below.
Also goggles must be worn to protect the eyes just in case of unexpected explosions or in case something is to spit up into ones face during the experiment, tongs also must be used to handle the mineral wool, as it is an irritant. Skin contact must be avoided. Calamine can also be an irritant and should be treated and handled in the same manner Suitable Range The range of readings in which I ‘m going to take are between 1. 0g and 3. 5g of Calamine. I am going to take 6 readings. These will be 1. 0g, 1. 5g, 2. 0g, 2. 5g, 3. 0g and 3. 5g. In order to produce an accurate conversion chart, at least 5 readings must be taken.
I have done 6 in case of any anomalies. The reason for choosing these particular measurements of Calamine is because they are spaced out evenly and easy to compare. Also these are the boundaries of our limitations. Research shows me that the largest amount of Calamine to put into the test tubes, keeping the experiment safe, is about 3. 5g, therefore I have chosen this quantity as the biggest amount to be used. Method First we will get our equipment out and set it up. The test tube will then be weighed and recorded using the electronic scales. After that, the Calamine is placed into the test tube.
This is then weighed using the same scales. To find out how much Calamine you have in the test tube, you simply deduct the weight of the test tube from the new weight (with the Calamine in the test tube). E. g. If the test tube weighed 15. 54g, and with the Calamine in the test tube it weighed 16. 00g, you could establish the weight of Calamine as being 16. 00g-15. 54g=0. 46g The mineral wool is then placed in at the mouth of the test tube. This is then weighed all together and recorded. This weight can then be used later to establish the individual weights of everything in the test tube.
Jack Mariner Chemistry Coursework Next, the Bunsen burner can be set up, ready to work. This will be positioned on a heatproof mat so as not to burn the working surface underneath. The flame will be on a roaring blue flame, and the bottom of the test tube will then be placed at the top of the inner blue cone (hottest point). See (pic 1). This will stay here for 2 minutes. We will then wait for the test tube to cool down; at that time we will weigh the test tube and its contents using the same electronic scales as before, subsequently recording the results. We will then return the test tube to the Bunsen burner.