   Chapter 16, Problem 85GQ

Chapter
Section
Textbook Problem

About this time, you may be wishing you had an aspirin. Aspirin is an organic acid with a Ka of 3.27 × 10−4 for the reaction.HC9H7O4(aq) + H2O(ℓ) ⇄ C9H7O4−(aq) + H3O+(aq)If you have two tablets, each contains 0.325 g of aspirin (mixed with a neutral “binder” to hold the tablet together), and you dissolve then in a glass of water to give 225 mL of solution, what is the pH of the solution.

Interpretation Introduction

Interpretation:

pH of the solution has to be determined which is prepared by the 0.325g of aspirin is dissolved in 225 ml of water.

Concept introduction:

Equilibrium constants:

The equilibrium constant is used to quantitative measurement of  the strength of the acid and bases in the water .

Ka is an acid constant for equilibrium reactions.

HA + H2OH3O++ A-Ka[H3O+][A-][HA]

Kb is a base constant for equilibrium reaction.

BOH + H2OB++ OH-Ka[B+][OH-][BOH]

Ion product constant for wter  Kw= [H3O+][OH-]       =1.00×10-14 pH = -log[H3O+]pOH= -log[OH-]Reltion between pH and pOH pH + pOH =14

Explanation

Let’s calculate the concentration of aspirin:

Given mass of aspirin =0.325g

Mass of two aspirin tablets =  0.325g HC9H7O41 tablet HC9H7O4 × 2 tablets HC9H7O4= 0.65g  HC9H7O4

Convert the volume millilitres into litre.

Given volume =225mL

= 225mL × 1L1000mL= 0.225L

Concentration of aspirin =moles of aspirinVolume of solution(L)=(0.65g180g/mol)0.225L=1.6×10-2M

Therefore, concentration of aspirin is 1.6×10-2 M.

Aspirin interacts with water. The equilibrium chemical reaction is as follows.

HC9H7O4(aq) + H2O(l) C9H7O4-(aq) + H3O+(aq)

The equilibrium expression:

Ka[C9H7O4-][H3O+][HC9H7O4]

Enter the ICE table the concentrations before equilibrium is established, the change that occurs as the reaction proceeds to equilibrium and the concentrations when equilibrium has been achieved.

HC9H7O4(aq) + H2O(l) C9H7O4-(aq) + H3O+(aq)I       1.6×102                 --                --                  --C          -x                        --              + x               + xE    (1

Still sussing out bartleby?

Check out a sample textbook solution.

See a sample solution

The Solution to Your Study Problems

Bartleby provides explanations to thousands of textbook problems written by our experts, many with advanced degrees!

Get Started

What are some functions of skin?

Human Biology (MindTap Course List)

Describe the function of the enzyme halicase in the replication of DNA.

Chemistry for Today: General, Organic, and Biochemistry

are removed from new mRNAs. a. Introns b. Exons c. Telomeres d. Amino adds

Biology: The Unity and Diversity of Life (MindTap Course List) 