Edexcel AS level Unit 3B: Chemistry Laboratory Skills I Alternative May 7 2014

guys new question from may 13

Using the same equipment, together with a stop clock, suggest a procedure
that would improve the accuracy of this experiment by obtaining a more accurate
temperature change. You must use the same mass of zinc powder and the same
volume of 1.00 mol dm–3 copper(II) sulfate solution.

like can you please explain step by step properly on what to do and not just list points from the mark scheme.. this question is weeeird!

thanks

guys new question from may 13

Using the same equipment, together with a stop clock, suggest a procedure
that would improve the accuracy of this experiment by obtaining a more accurate
temperature change. You must use the same mass of zinc powder and the same
volume of 1.00 mol dm–3 copper(II) sulfate solution.

like can you please explain step by step properly on what to do and not just list points from the mark scheme.. this question is weeeird!

thanks

no one has notes? or at least can someone list the experiments?

1. take several measurements of temp of cuso4 solution before adding Zn metal
2. at 3.5 mins exactly add zn and continue taking the measurements of temp for 10 mins.
3. draw a graph of temp. and time
4.extrapolate graph at exactly 3.5 mins to get the highest temp that could be reached.


soo i guess , if i understood correctly, that instead of having a stop watch in ur hand , and putting Zn powder into the solution and then quickly hold the thermometer and measure initial and final temp (which will be inaccurate ) , just use a graph to extrapolate which will be much more accurate. As the first method u wont be fast enough and accurate enough to measure the highest temp reached (final temp.)

i hope u understood something i explain really bad

guys new question from may 13

Using the same equipment, together with a stop clock, suggest a procedure
that would improve the accuracy of this experiment by obtaining a more accurate
temperature change. You must use the same mass of zinc powder and the same
volume of 1.00 mol dm–3 copper(II) sulfate solution.

like can you please explain step by step properly on what to do and not just list points from the mark scheme.. this question is weeeird!

thanks

Hey i have some notes ! Learn everything i've attached and don't worry.

•pipette out 50cm3 of copper (ll) sulfate into a polystyrene cup and start stopwatch and measure the temperature simultaneously.

•record the temperature every 3 minutes. At 3.5 minute add solid and stir the mixture.

•then measure temperature from 4th minute to 10th minute.

•plot a graph of temperature against time. Connect the points before addition of solid and extrapolate it to the time of adding the solid. Connect the points after adding the solid and extra Polate back to the time of adding


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Can someone please answer all these questions?


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new question from JAN 14! the IR SPECTRUM! does anyone have any logical proper wonderful explanation as to why the spectrum is for Hex-5-en-1ol and not for the cycloalkene??? i mean it could correspond to both but the cycloalkene is like 90 percent correct in my opinion

but the mark scheme says its the latter help?

@Miffyy my answers are being checked by moderators, sorry !!

guys!!!
do u know why we use anti bumping granules when distilling or doing reflux