Straight line

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Lucia H 2L
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Straight line

Postby Lucia H 2L » Thu Mar 01, 2018 11:48 pm

Why does a straight line mean that the reaction is the correct order to match the graph? Is it because a straight line represents the best fit line?

Emily Oren 3C
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Joined: Fri Sep 29, 2017 7:07 am

Re: Straight line

Postby Emily Oren 3C » Fri Mar 02, 2018 12:07 am

Yes, the straight line is a best fit line to the data. When trying to determine the order of a reaction from the data, you need to plot the data and see what operation you need to do to make the best fit curve be a straight line instead of an exponential decay or other nonlinear graph. For example, if plotting the experimental data on a ln[A] vs time graph gives a straight best fit line, then the reaction is first order. If plotting the data on a 1/[A] vs time graph gives a straight line, then the reaction is second order. You may need to plot it multiple times to find the correct one. I hope this helps!

Riya Pathare 2E
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Re: Straight line

Postby Riya Pathare 2E » Fri Mar 02, 2018 10:35 am

Generally if you plot the ln[A] vs time or 1/[A] vs time and its not first or second order then it should form an evidently curved line in stead of straight like an exponential decay function.

Clara Hu 1G
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Re: Straight line

Postby Clara Hu 1G » Fri Mar 02, 2018 12:39 pm

Also, if you plot a straight line with [A] vs t, it is zero order. ln[A] vs t means that it is first order, and 1/[A] vs t is second order.

Chris Lamb 1G
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Joined: Fri Jun 23, 2017 11:39 am

Re: Straight line

Postby Chris Lamb 1G » Fri Mar 02, 2018 1:01 pm

Each order produces a straight line when the y axis is set to a specific function of concentration.

Magdalena Palavecino 1A
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Re: Straight line

Postby Magdalena Palavecino 1A » Sat Mar 03, 2018 12:50 pm

It is also important to note that the slopes of these graphs will be either -k or k

Christy Zhao 1H
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Joined: Fri Sep 29, 2017 7:07 am

Re: Straight line

Postby Christy Zhao 1H » Sun Mar 04, 2018 2:39 pm

Adding on to the comment above, -k would be for zero and first-order reactions, and k would correspond to second-order reactions.

Guadalupe T 1E
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Joined: Fri Sep 29, 2017 7:04 am

Re: Straight line

Postby Guadalupe T 1E » Tue Mar 06, 2018 3:35 pm

If you were given three graphs and were asked what order it is, you'd have to look at the one with a straight line to tell.


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