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On the Lighter Side => Science Experiments => Topic started by: scientizscht on 04/08/2019 23:01:24

Title: How can I calculate mass from a concentration/time graph?
Post by: scientizscht on 04/08/2019 23:01:24

Hello

I have a graph that shows the concentration of a product increasing as a reaction takes place.

Let's say that graph is a straight link y=ax starting from zero at time = 0 and goes to 1M when time = 1 hour.

How can I calculate from that the amount of that product in the solution of 1L?

I was tempted to calculate the area under the line but that would give units of Mxh which does not make sense.

Any idea?

Title: Re: How can I calculate mass from a concentration/time graph?
Post by: evan_au on 05/08/2019 05:55:30

In general, reaction rates are not a straight line.

In a closed container, as the reactants become more dilute, the reaction rates decline.

A negative-exponential rate is more realistic.

Title: Re: How can I calculate mass from a concentration/time graph?
Post by: scientizscht on 05/08/2019 13:21:05

Quote from: evan_au on 05/08/2019 05:55:30

In general, reaction rates are not a straight line.

In a closed container, as the reactants become more dilute, the reaction rates decline.

A negative-exponential rate is more realistic.

I know but the whole point of the question is different.
As I said, let's assume a straight line.
How can the amount of the product be calculated from that graph?

Title: Re: How can I calculate mass from a concentration/time graph?
Post by: Bored chemist on 05/08/2019 19:38:08

What does 1M mean in this?

Quote from: scientizscht on 04/08/2019 23:01:24

goes to 1M when time = 1 hour.

Title: Re: How can I calculate mass from a concentration/time graph?
Post by: scientizscht on 05/08/2019 22:30:12

Quote from: Bored chemist on 05/08/2019 19:38:08

What does 1M mean in this?

Quote from: scientizscht on 04/08/2019 23:01:24

goes to 1M when time = 1 hour.

Molarity
(are you surely a chemist?)

Title: Re: How can I calculate mass from a concentration/time graph?
Post by: alancalverd on 10/08/2019 11:18:35

Quote from: scientizscht on 04/08/2019 23:01:24

I have a graph that shows the concentration of a product increasing as a reaction takes place.

So that well be moles/liter  (concentration) on the y axis, and hours on the x-axis, and the concentration at any time will be the y  value for that time.

Title: Re: How can I calculate mass from a concentration/time graph?
Post by: Bored chemist on 10/08/2019 13:50:26

Quote from: scientizscht on 05/08/2019 22:30:12

Quote from: Bored chemist on 05/08/2019 19:38:08

What does 1M mean in this?

Quote from: scientizscht on 04/08/2019 23:01:24

goes to 1M when time = 1 hour.

Molarity
(are you surely a chemist?)

I'm a chemist, so it's obvious that I know what it means.
So it's clear that I'm not asking you so that I can find out.

Now, let's try again
What does the M mean, (or if you like, what does "molarity" mean)?

Title: Re: How can I calculate mass from a concentration/time graph?
Post by: Bored chemist on 10/08/2019 13:55:35

Quote from: scientizscht on 04/08/2019 23:01:24

I have a graph that shows the concentration of a product increasing as a reaction takes place.

Let's say that graph is a straight link y=ax starting from zero at time = 0 and goes to 1M when time = 1 hour.

How can I calculate from that the amount of that product in the solution of 1L?

I was tempted to calculate the area under the line but that would give units of Mxh which does not make sense.

Any idea?