Finding mass percentage of LSD in salt by combustion analysis

[mh90]

Hi, this is my first question, and I'm working on some summer work with a friend and we stumbled upon this problem.

Homework Statement

A sample of LSD is added to table salt (sodium chloride) given that a 1.00 g sample of a mixture undergoes combustion to reduce 1.20g of CO2, what is the mass percentage of LSD in the mixture.

Homework Equations

This type of LSD is C24H30N30

The Attempt at a Solution

We tried to balance the combustion reaction, knowing that combustion gives us the products CO2 and H20, but we can't figure out the other products and without a balanced equation we can't do the problem.

 

[berkeman]

Uh, just to clarify. Is LSD Low Sulphur Diesel?

 

[mh90]

Oh, sorry, LSD would be D-Lysergic Acid Diethylamide.

 

[berkeman]

Oh, sorry, LSD would be D-Lysergic Acid Diethylamide.

Ah, got it. Like from acronymfinder.com:

LSD : d-Lysergic Acid Diethylamide (psychedelic drug)

Do you have a license for handling that drug? Kind of a strange chemistry experiment, no?

 

[Gokul43201]

Berke, it's not an experiment - just a textbook problem.

mh90, what are the reactants and products of the combustion reaction? Do you know how to balance an equation?

 

[mh90]

We don't know the reactants, we only know that it is a combustion reaction.

C24H30N3O + O2 ---> CO2 + H2O

We also know that mixes with NaCl.

C24H30N3O + NaCl + O2 ---> CO2 +H2O

That's what are problem is, what are the other reactants.

 

[Gokul43201]

We don't know the reactants, we only know that it is a combustion reaction.

C24H30N3O + O2 ---> CO2 + H2O

Well, C24H30N3O and O2 are the reactants! In addition to CO2 and H2O, there will be come mixture of nitrogen oxides which are produced - these are not important.

We also know that mixes with NaCl.

C24H30N3O + NaCl + O2 ---> CO2 +H2O

That's what are problem is, what are the other reactants.

There are no others. Also NaCl does not participate in the combustion, so can be left out of the equation.

That leaves you with:

C24H30N3O + O2 ----> CO2 + H2O + NOx

The next step is to balance the number of C-atoms in the above equation. How do you do that?

You don't need to worry about the H2O or NOx for this question.