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  1. Z

    Chemo P5 tips

    Yep that is the formula
  2. Z

    Chemo P5 tips

    How to purify an organic liquid ( such as cyclohexene) that is contaminated with acid: 1. Add NaHCO3 in excess. This reacts with the acid to neutralize it 2. Wash off the NaHCO3 from the organic liquid using water (NaHCO3 is aqueous) 3. Add drying agent to the solution to remove water 4...
  3. Z

    Chemo P5 tips

    Errors in measuring enthalpy change: 1. Maximum temperature difficult to determine Measure temperatures often or use a computer and datalogger to measure the temperature 2. The temperature of the solution is not uniform Stir the solution throughout the experiment or use a magnetic stirrer...
  4. Z

    Chemo P5 tips

    what do u mean by a new product formed on removing moisture? nd can u give an example of drying agent ?[ Drying simply is removing the water present in the crystal due to its treatment during the course of experiment. I have mentioned the examples of drying agent in one of my posts. An example...
  5. Z

    Chemo P5 tips

    If asked in an enthalpy experiment what effect does incomplete value of ethanol have on the measured enthalpy change of combustion: 1. Value decreased 2. Because less C=O bonds formed
  6. Z

    Chemo P5 tips

    Drying agent:Drying agents absorb the moisture contents from a substance Dehydrating agent: dehydration removes the water molecules, hence totally a new product is formed
  7. Z

    Chemo P5 tips

    we aren't expected to know about it, I think but if you wanted to know about "Mel Temp" you could google it!
  8. Z

    Chemo P5 tips

    all I meant to say was if you have a magnesium ribbon covered with dirt, you cannot expect to react it properly with HCl!!!!!!!!! So, use sandpaper to get rid of the dirt. nothing much really, just popped up in my mind!
  9. Z

    Chemo P5 tips

    It would be better if you mention that you use a wash bottle or a funnel to fill the flask upto the mark (CIE won't be this specific though :D ) You will have to mention how you make the concentration of 1.00, 1.25 (mention relative volumes of solution + water) Everything else is great!
  10. Z

    Chemo P5 tips

    What does "jet space" refer to with regards to a burette?
  11. Z

    Chemo P5 tips

    Very commonly asked procedures: 1. Titration: 1. acid-alkali titration Don’t forget to: - rinse the burette with acid - rinse the pipette with alkali - When emptying the pipette into the conical flask, allow it to empty under gravity, and then touch the surface of the liquid with the...
  12. Z

    Chemo P5 tips

    suppose you had to reduce CuO. You would have to heat the solid in a container with H2 gas. But we already have some air (which contains oxygen) present in the container initially. So, the reduced Cu will keep on getting oxidised until all of the O2 in the container has not reacted and this will...
  13. Z

    Chemo P5 tips

    sorry, you have to take 125 cm3 of the parent solution! you are absolutely correct and great spotting
  14. Z

    Chemo P5 tips

    In analytical chemistry, a standard solution is a solution containing a precisely known concentration of an element or a substance. It is prepared using a standard substance, such as a primary standard. Standard solutions are used to determine the concentrations of other substances, such as...
  15. Z

    Chem P5 most common planning questions and topics

    guys, can you please explain what a divided flask is??
  16. Z

    Chemo P5 tips

    the thing is in our practical, most solutions primarily consist of water and the density of water is 1g/cm3. So, 1 cm3 corresponds to 1 gram. Thus for any solution, you could either use its mass or its volume, the numerical value will be the same. However, it is technically correct to use the...
  17. Z

    Chemo P5 tips

    If you are using an excess of alkali then the expression has to divided by the number of moles of acids
  18. Z

    Chemo P5 tips

    If it is a simple dilution, you could use a 250 cm3 beaker. We are measuring the real deal using burette or the pipette. However, if you want to mix the solution really well, you could use the graduated flask. I think I will just stick with the 250cm3 beaker for now.
  19. Z

    Chemo P5 tips

    Suppose you are given a solution with concentration 1.0 mol/dm3 and you have to serially dilute it to various concentrations then: Volume of solution / cm3 Volume of water/cm3 Relative concentration 50...
  20. Z

    Chemo P5 tips

    if the experiment involves plotting a pH against volume curve, the accuracy of the curve can be increased by using data logger interface and computer combined together to plot the graph
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