Monosodium glutamate (MSG), a food-flavor enhancer, has been blamed for “Chinese Restaurant Syndrome,” the symptoms of which are headaches & chest pains. MSG has the following composition by mass: 35.51 percent C, 4.77 percent H, 37.85 percent O, 8.29 percent N, & 13.60 percent Na. What is its molecular formula if its molar mass is about 169 g?
I don't know how to start this problem, please help!!
2 answers
start by figuring out what 35.51 percent of 169 grams is. It is around 60 grams (60.0119g to be exact) this is the percentage of carbon in MSG. Now look at the bottom number on the periodic table for carbon 12.01, meaning one Mol is 12.01g, therefore 5 carbons will be needed for 60 grams... 60/12 = 5. So you have your first part of the formula C5. (169 * 0.3551 gives you the 60.0119)
I disagree with the way Kyle has worked the problem. I've posted by answer at your first query. Kyle's solution will give you the correct answer but it is based on his assumption (Kyle may not have assumed that in his mind but his solution does that automatically) that the simplest empirical formula and the molecular formula are the same. It turns at that is correct but if that were not so his method would not work.
2 answers