[tomgreenschic]

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.

[Astrokel]

387 is correct

[tomgreenschic]

uh oh. are you sure? because I did it again and got 129 g of soap.
thanks so much.

[Borek]

387 was incorrect.

Your molar mass of the soap was not correct - formula of the soap is NaC₁₇H₃₅CO₂, not 3NaC₁₇H₃₅CO₂.

129 is OK.

[Astrokel]

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.

[Borek]

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.

[JGK]

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

[Borek]

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.