F 5 Percent Composition

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Andrea- 3J
Posts: 56
Joined: Tue Nov 14, 2017 3:00 am

F 5 Percent Composition

Postby Andrea- 3J » Thu Oct 04, 2018 9:40 pm

What is the mass percentage composition of l-carnitine, C7H15NO3, a compound that is taken as a dietary supplement to reduce muscle fatigue?

I am having trouble fully understanding this problem. The problem does not state which element I need to find the percent composition for. You find mass percentage by dividing the grams of an element by the molar mass of the compound and multiplying it by 100%. But the problem does not specify which element I must solve for. Or am I understanding this problem incorrectly?

Patrick Cai 1L
Posts: 93
Joined: Fri Sep 28, 2018 12:25 am

Re: F 5 Percent Composition

Postby Patrick Cai 1L » Thu Oct 04, 2018 9:47 pm

Yea, for this question it asks for the mass percentage composition which is basically asking for the mass percentages of all elements present in l-carnitine. It can be easy to miss that one word that gives you the entire question, I did that in my first reading of the question too.

Celeste 1I
Posts: 44
Joined: Fri Sep 28, 2018 12:18 am

Re: F 5 Percent Composition

Postby Celeste 1I » Thu Oct 04, 2018 9:48 pm

Its asking you to find the percent composition of each element, I think. If you assume you have 100g of L-carnitine then it makes it pretty easy to find the percentage.

Alma Carrera 3C
Posts: 33
Joined: Fri Apr 06, 2018 11:02 am

Re: F 5 Percent Composition

Postby Alma Carrera 3C » Thu Oct 04, 2018 9:49 pm

You have to find the mass percentage of each element. In order to do this, first find the molar mass of each element and add them up to get the total molar mass of the compound, C7H15NO3. Then divide the molar masses of each element by the total molar mass of the compound and multiply by 100 to get the mass percentages. Hope this helps!

Hovik Mike Mkryan 2I
Posts: 95
Joined: Fri Sep 28, 2018 12:25 am

Re: F 5 Percent Composition

Postby Hovik Mike Mkryan 2I » Thu Oct 04, 2018 9:50 pm

Hello,
I did this problem by individually dividing the elements by the total mass (161.20g) and getting the percent composition of each element of the compound. Using 4 significant figures I got the percentage composition to be 52.15%C, 9.379%H, 8.691% N, and 29.78%O. I hope this helped!


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