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Recently Asked Questions
- For my A2 investigation I am looking at a kinetics reaction involving urea and urease and measuring the change in pH, I cannot find any useful information. Could you possibly point me in the direction of some helpful information?
- I am currently investigating the iodine clock reaction involving hydrogen peroxide. I don't understand how to work out if the overall equation is redox, especially in view to oxidation numbers? I also understand that the overall reaction can be split into 'half-equations' but am not sure how to go about this. 210208
- Hi, I need to know the answer to this question; "Draw 'dot and cross' diagrams for the following ionic compound, magnesium nitrate, showing all electrons. Show the charge on each ion in your diagrams." I don't know how to work out the electron configuration of nitrate, nor do I understand how it ionically bonds with the magnesium, please help!!
- In the back titration of insoluble metal carbonates with standard nitric acid and sodium hydroxide solution, why are dilute HCl and H2SO4 are not suitable?
- I am starting my vinegar investigation and am confused about the distillation. Firstly, I started with a round-bottomed flask and attached a stillhead and inserted a screwcap adaptor into this and then a thermometer. I added the Leibig condenser with rubber tubing. Then it became difficult at the final stage. As I need to collect the distillate over ice, I’m not sure what to use. Should I add a receiver adaptor leading into another round bottomed flask with this flas submerged in the ice bath? Or is there something else I could use so I do not lose the distillate to evaporation? Once I have this set up, do I titrate the distilled vinegar straight away or do I need to dilute this with distilled water? Could I do exactly the same with malt vinegar or do I need to decolourize this first? Is there a precise amount of vinegar I should add to the flask to begin with or should I just guess how much will give me enough product and also leave me with enough non-volatile liquid to titrate? What temperature should I be aware of on the thermometer and is it possible for me to seal both the products and reactants for titration on a different day? 210208
- What is the main advantage of 2-dimensional paper chromatography over a 1-dimensional one? What are the considerations in choosing a chromatographic solvent?
- Why is benzoic acid less reactive to electrophiles than benzene?
- I have investigated the sulphur dioxide content in the white wine. I use an iodine titration to determine the SO2 content, but I don't know why it is necessary to add sodium hydroxide solution to the wine before adding sulphuric acid. Can you tell me the purpose?
- I am trying to find out the order of the reaction between hydrochloric acid and Mg, by measuring the rate at which hydrogen is produced. I have found that the test-tube gets very hot during the reaction, therefore I am going to carry out the reaction in a waterbath - to ensure that the temperature remains constant. Should the water be cold or at room temperature (about 20 oC)?
- If you heat 3.970 g of a mixture of Fe3O4 and FeO to form 4.195 g of Fe2O3, what is the mass percent of FeO originally in the mixture? 260308
updated: 02 January 2008
