## Straight line

Lucia H 2L
Posts: 43
Joined: Mon Nov 14, 2016 3:00 am
Been upvoted: 1 time

### Straight line

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
Posts: 50
Joined: Fri Sep 29, 2017 7:07 am

### Re: Straight line

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
Posts: 74
Joined: Sat Jul 22, 2017 3:01 am
Been upvoted: 1 time

### Re: Straight line

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
Posts: 50
Joined: Sat Jul 22, 2017 3:00 am
Been upvoted: 1 time

### Re: Straight line

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
Posts: 58
Joined: Fri Jun 23, 2017 11:39 am

### Re: Straight line

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

Magdalena Palavecino 1A
Posts: 54
Joined: Fri Sep 29, 2017 7:04 am

### Re: Straight line

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

Christy Zhao 1H
Posts: 50
Joined: Fri Sep 29, 2017 7:07 am

### Re: Straight line

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