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Ch.23 Lipids
McMurry - Fundamentals of General, Organic, and Biological Chemistry 8th Edition
McMurry8th EditionFundamentals of General, Organic, and Biological ChemistryISBN: 9780134015187Non è quello che usi tu?Cambia libro di testo
Capitolo 23, Problema 86

If the average molar mass of a sample of soybean oil is 1500 g/mol, how many grams of NaOH are needed to saponify 5.0 g of the oil?

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Determine the number of moles of soybean oil in the sample by using the formula: \( \text{moles of oil} = \frac{\text{mass of oil (g)}}{\text{molar mass of oil (g/mol)}} \). Substitute the given values: mass of oil = 5.0 g and molar mass of oil = 1500 g/mol.
Understand the saponification reaction: Each molecule of triglyceride (soybean oil) reacts with 3 moles of NaOH to produce glycerol and soap. Therefore, the mole ratio of oil to NaOH is 1:3.
Calculate the moles of NaOH required by multiplying the moles of oil by the mole ratio (3 moles of NaOH per 1 mole of oil). Use the formula: \( \text{moles of NaOH} = \text{moles of oil} \times 3 \).
Convert the moles of NaOH to grams using the molar mass of NaOH (40.00 g/mol). Use the formula: \( \text{mass of NaOH (g)} = \text{moles of NaOH} \times \text{molar mass of NaOH (g/mol)} \).
Summarize the process: First, calculate the moles of oil, then determine the moles of NaOH needed using the reaction stoichiometry, and finally convert the moles of NaOH to grams to find the required mass of NaOH.

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Saponification

Saponification is a chemical reaction that occurs when a fat or oil reacts with a strong base, typically sodium hydroxide (NaOH), to produce glycerol and soap. This process is essential in the production of soap from triglycerides found in oils and fats. Understanding this reaction is crucial for calculating the amount of base needed to fully react with a given mass of oil.
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Ester Reactions: Saponification Concept 1

Stoichiometry

Stoichiometry is the branch of chemistry that deals with the quantitative relationships between the reactants and products in a chemical reaction. It allows us to calculate the amounts of substances involved based on their molar masses and the balanced chemical equation. In this context, stoichiometry is used to determine how much NaOH is required to saponify a specific mass of soybean oil.
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Molar Mass

Molar mass is the mass of one mole of a substance, expressed in grams per mole (g/mol). It is a critical factor in stoichiometric calculations, as it allows for the conversion between the mass of a substance and the number of moles. In this question, the average molar mass of soybean oil is given, which is necessary for determining the moles of oil present and subsequently calculating the required grams of NaOH.
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Calculating Molar Mass