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### First order graph

Posted: **Tue Mar 05, 2019 2:51 pm**

by **Amy Lefley 1J**

When graphing a first order reaction, with time on the x-axis and ln(A) on the y-axis, the y-intercept is the natural log of the initial concentration of the reactant, but what does the x-intercept of this graph represent?

### Re: First order graph

Posted: **Tue Mar 05, 2019 2:54 pm**

by **Gillian Murphy 2C**

time

### Re: First order graph

Posted: **Tue Mar 05, 2019 3:34 pm**

by **Rachel-Weisz3C**

It represents time and it is usually measured in seconds, therefore rate = M/s, but it can also be measured in minutes, hours... depending on the reaction.

### Re: First order graph

Posted: **Tue Mar 05, 2019 4:20 pm**

by **Heesu_Kim_1F**

The x-intercept (meaning y=0) of the first order graph would represent the time (usually in seconds) when the concentration of the reactant reaches 0, or essentially when there is no more reactant concentration left.

Hope this helps!

### Re: First order graph

Posted: **Thu Mar 07, 2019 12:21 pm**

by **Megan_Ervin_1F**

If ln(A) vs Time is a straight line, then the reaction is a first order reaction

### Re: First order graph

Posted: **Thu Mar 07, 2019 2:45 pm**

by **mbaker4E**

The x axis is time, usually in seconds but it can also be in minutes, days, etc.

### Re: First order graph

Posted: **Thu Mar 07, 2019 3:44 pm**

by **varunhariharan**

The x-intercept shows how much time time (t) it takes for the natural log of [A] to equal zero, and for [A] to equal zero.

### Re: First order graph

Posted: **Thu Mar 07, 2019 3:47 pm**

by **Nicole Lee 4E**

The x-intercept would tell you the time at which all of your reactant A runs out.