Chemical Forums
Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: tomgreenschic on November 05, 2008, 05:55:41 PM
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One method used to make soap, NaC17H35CO2, includes the reaction between NaOH and animal fat, C3H5(C17H35CO2)3 according to the following balanced equation:
C3H5(C17H35CO2)3 + 3 NaOH ----> C3H5(OH)3 + 3NaC17H35CO2
1. How many grams of soap would theoretically be produced by starting with 125g of animal fat?
I figured it out to be 387g. I'm just not entirely sure I did it correctly.
I found the molar mass of animal fat to be 890g and the molar mass of soap to be 918.
Any help would be GREATLY appreciated. Thanks much.
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387 is correct
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uh oh. are you sure? because I did it again and got 129 g of soap.
??? thanks so much.
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387 was incorrect.
Your molar mass of the soap was not correct - formula of the soap is NaC17H35CO2, not 3NaC17H35CO2.
129 is OK.
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uh oh. are you sure? because I did it again and got 129 g of soap.
thanks so much.
Ye you are right as Borek has already said, as i worked out the question assuming your molar mass stated was correct.
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i worked out the question assuming your molar mass stated was correct.
That's why I like to check such questions with EBAS, it helps to catch stupid mistakes.
Although in this case error was obvious - molar mass of the soap must be about three times lower than the molar mass of the triglyceride.
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387 was incorrect.
Your molar mass of the soap was not correct - formula of the soap is NaC17H35CO2, not 3NaC17H35CO2.
129 is OK.
Where did the other 2 sodiums go? or should it be Na3C17H35CO2
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Where did the other 2 sodiums go? or should it be Na3C17H35CO2
To two OTHER soap molecules. Three are produced, each with NaC17H35CO2 formula, and molar mass of 306.46.