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Ch.14 Carboxylic Acids, Esters, Amines, and Amides
Timberlake - Chemistry: An Introduction to General, Organic, and Biological Chemistry 13th Edition
Timberlake13th EditionChemistry: An Introduction to General, Organic, and Biological ChemistryISBN: 9780134421353Not the one you use?Change textbook
Chapter 14, Problem 38b

Write the balanced chemical equations for the (1) reaction of each of the following amines with water and (2) neutralization with HBr:
b. propylamine

Verified step by step guidance
1
Step 1: Understand the problem. Propylamine (C₃H₇NH₂) is a primary amine. When it reacts with water, it acts as a weak base, accepting a proton (H⁺) from water to form its conjugate acid and hydroxide ions (OH⁻). In the neutralization reaction with HBr, the amine reacts with the acid to form an ammonium salt.
Step 2: Write the reaction of propylamine with water. The general reaction for an amine (RNH₂) with water is: RNH₂ + H₂O ⇌ RNH₃⁺ + OH⁻. For propylamine, substitute R with C₃H₇: C₃H₇NH₂ + H₂O ⇌ C₃H₇NH₃⁺ + OH⁻.
Step 3: Balance the reaction of propylamine with water. Ensure that the number of atoms on both sides of the equation is equal. In this case, the equation is already balanced as written: C₃H₇NH₂ + H₂O ⇌ C₃H₇NH₃⁺ + OH⁻.
Step 4: Write the neutralization reaction of propylamine with HBr. The general reaction for an amine (RNH₂) with a strong acid (HX) is: RNH₂ + HX → RNH₃⁺X⁻. For propylamine, substitute R with C₃H₇ and X with Br: C₃H₇NH₂ + HBr → C₃H₇NH₃⁺Br⁻.
Step 5: Balance the neutralization reaction. Ensure that the number of atoms and charges are balanced. In this case, the equation is already balanced as written: C₃H₇NH₂ + HBr → C₃H₇NH₃⁺Br⁻.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Balanced Chemical Equations

A balanced chemical equation represents a chemical reaction where the number of atoms for each element is the same on both sides of the equation. This is crucial for adhering to the law of conservation of mass. Balancing involves adjusting coefficients to ensure that reactants and products have equal numbers of each type of atom.
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Amines and Their Reactions

Amines are organic compounds derived from ammonia by replacing one or more hydrogen atoms with alkyl or aryl groups. They can act as bases, reacting with water to form ammonium ions and hydroxide ions. Understanding the behavior of amines in aqueous solutions is essential for predicting their reactions with acids like HBr.
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Neutralization Reactions

Neutralization reactions occur when an acid reacts with a base to produce water and a salt. In the case of amines, when they react with strong acids like HBr, they form an ammonium salt. This concept is fundamental in understanding how amines behave in acidic environments and the products formed from such reactions.
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