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# Calculating rate of reaction pls help ! Watch

1. Attachment 567658567660 Here is my answer to part c of this question.
Firstly, I want to know whether my squiggly line is drawn correctly because I don't normally use it
Secondly, I am not sure if I am supposed to join all the points together or just do a line of best fit for this kind of question. Have I done it right?
Thirdly, for my calculation, my inital rate is 9.09*10^-4 but the answer is 6.25*10^-4, what have I done wrong?

Many thanks
Attached Images

2. Your working looks fine to me, the initial rate is the gradient of the line when t=0 as you've identified.

I think the error in your answer arises from the fact that it is hard to accurately draw a tangent to a hand drawn line of best fit.So the error is nothing to do with your chemistry or your understanding its just a bit of human error which is hard to avoid (could use a computer to do the plot?)
3. (Original post by MexicanKeith)
Your working looks fine to me, the initial rate is the gradient of the line when t=0 as you've identified.

I think the error in your answer arises from the fact that it is hard to accurately draw a tangent to a hand drawn line of best fit.So the error is nothing to do with your chemistry or your understanding its just a bit of human error which is hard to avoid (could use a computer to do the plot?)
Thanks for the reply. So for this kind of question, am I supposed to draw line of best fi(I vaguely remembered being told to do so)? However, it doesn't seem necessary to do so in this question, so I just plotted the points together but not very accurately though.
Thanks
4. (Original post by coconut64)
Thanks for the reply. So for this kind of question, am I supposed to draw line of best fi(I vaguely remembered being told to do so)? However, it doesn't seem necessary to do so in this question, so I just plotted the points together but not very accurately though.
Thanks
I would say a line of best fit isn't necessary, it doesn't really tell you much about the data, a line that runs through the points is more informative.

If you know about order of reactions, you can see what the graphs of concentration vs time should look like for zeroeth, first and second order reactions in the attachment which is (hopefully) attached
Attached Images

5. (Original post by MexicanKeith)
I would say a line of best fit isn't necessary, it doesn't really tell you much about the data, a line that runs through the points is more informative.

If you know about order of reactions, you can see what the graphs of concentration vs time should look like for zeroeth, first and second order reactions in the attachment which is (hopefully) attached
Hi, for the curve graph, if a line of best fit is not used then it wouldn't be as curvy though because like what I did, it looks more like a straight line then a curve if I am to plot all the points together. Thanks

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