Solve Stoichiometry Help: Making a 405g Bar of Soap

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Discussion Overview

The discussion revolves around a stoichiometry problem related to the saponification process for making soap, specifically calculating the amounts of lard (trioleic acid) and lye (NaOH) needed to produce a 405g bar of soap. Additionally, a separate question regarding the reaction of aluminum with ammonium perchlorate is introduced, focusing on the mass of nitrogen vapor produced.

Discussion Character

  • Homework-related
  • Mathematical reasoning
  • Technical explanation

Main Points Raised

  • Post 1 outlines the stoichiometry problem and expresses uncertainty about how to approach the calculations needed to determine the amounts of lard and lye required.
  • Post 2 questions the accuracy of the chemical nomenclature used and suggests that the molar masses provided may not be reliable, indicating a need for clarification on how these values were derived.
  • Post 3 provides a corrected version of the saponification reaction and offers updated molar mass values for triolein and the resulting soap, but does not resolve the initial problem posed.
  • Post 4 shifts to a different question regarding a balanced chemical equation involving aluminum and ammonium perchlorate, expressing confusion over the notation "e5kg" and "e6kg" for mass inputs.

Areas of Agreement / Disagreement

Participants express differing views on the chemical nomenclature and the accuracy of the provided molar masses, indicating a lack of consensus on these points. The initial stoichiometry problem remains unresolved, and the second question introduces additional confusion without agreement on the notation used.

Contextual Notes

There are uncertainties regarding the definitions of the chemical compounds involved and the derivation of molar masses. The notation "e5kg" and "e6kg" is not clarified, leaving ambiguity in the second question.

Who May Find This Useful

This discussion may be of interest to students studying chemistry or those seeking assistance with stoichiometry problems, particularly in the context of saponification and combustion reactions.

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Homework Statement


Saponification is the process by which soap is made. A triglyceride is reacted with NaOH to produce a carboxylic acid salt (the soap) and glycerol
Lard, mostly made of trioleic acid (TOA) is used with Lye (NaOH) in homemade variations
molar mass of TOA is 848g/mol
molar mass of resulting soap is 304g/mol


Homework Equations


TOA + 3NaOH --> 3 Soaps+ 3 glycerol

Question: if you want to make a 405g bar of soap with no excess lard or lye what amounts of lard and lye are needed.

The Attempt at a Solution



i have no idea how to do this problem. I know you start with 405g soap/1 to 1mol soap/(idk how much soap weighs per mol)
 
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Firstly, you must realize that this question is a bit hypothetical since animal fats are saturated, unlike 'trioleic acid'. That would be tristearic acid in your nomenclature. An alternative nomenclature is to say 'triolein' for the glyceryl ester of oleic acid (olive oil) and 'tristearin' for the glyceryl ester of stearic acid (lard).

You are given the molar mass of the TOA and the resulting soap in the problem but I have no idea how those numbers were arrived at... perhaps thin air? The amount of soap produced from TOA is therefore given by a ratio of these two numbers multiplied by number. Can you take it from there?
 
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BTW, The correct saponification reaction (not your problem, certainly) would be:

[tex]Triolein + 3NaOH \rightarrow\ 3 Na^+ ^-OOC-C_{17}H_{33} + 1 glycerol[/tex]

where the formula weight of triolein is 885.4 g/mol and the formula weight of the soap is 304.4.
 
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a little more help

thanks a lot
heres another wuestion i need help with

the fuel used to power booster rockets is represented in The balanced equation
3Al + 3NH4CIO4 ? Al2O3 + 3NO + 6H2O

if ____e5kg Aluminum reacts with an excess of ammonium perchlorate (say____e6kg) what is the mass of nitrogen vapor produced

im supposed to fill in the blanks with any numbers that i want but i don't know what "e5kg" and "e6kg" mean.
 

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