Hydrophobic vs Hydrophillic pH and Buffers - PowerPoint PPT Presentation

Loading...

PPT – Hydrophobic vs Hydrophillic pH and Buffers PowerPoint presentation | free to view - id: 95e53-ZDQ5N



Loading


The Adobe Flash plugin is needed to view this content

Get the plugin now

View by Category
About This Presentation
Title:

Hydrophobic vs Hydrophillic pH and Buffers

Description:

Hydrophobic vs Hydrophillic. pH and Buffers. Lecture 6. Hydrophobicity. In chemistry, hydrophobicity (from the combining form of water in Attic Greek ... – PowerPoint PPT presentation

Number of Views:94
Avg rating:3.0/5.0
Slides: 15
Provided by: RandyA
Category:

less

Write a Comment
User Comments (0)
Transcript and Presenter's Notes

Title: Hydrophobic vs Hydrophillic pH and Buffers


1
Hydrophobic vs HydrophillicpH and Buffers
  • Lecture 6

2
Hydrophobicity
  • In chemistry, hydrophobicity (from the combining
    form of water in Attic Greek hydro- and for fear
    phobos) refers to the physical property of a
    molecule that is repelled from water.
  • Hydrophobic molecules tend to be non-polar and
    thus prefer other neutral molecules and nonpolar
    solvents.
  • Examples of hydrophobic molecules include the
    oils, fats, and greasy substances in general.

3
Hydrophophilicity
  • A hydrophilic molecule or portion of a molecule
    is charge-polarized and capable dissolving more
    readily in water than in oil. Hydrophilic
    molecules are also known as polar molecules.

4
Acid
  • Any substance that when dissolved in water will
    donate a hydrogen ion to the solution or increase
    the hydrogen ion concentration of the solution
  • Typically the chemical formula will have a
    Hydrogen in it (HCl, CH3COOH).
  • HA ? H A-

5
Base
  • Any substance that when dissolved in water will
    decrease the hydrogen ion concentration
  • Typically bases will have an OH in the chemical
    formula (NaOH)
  • B- H ? BH

6
Strong or Weak?
The strength of the acid or base is dependent on
the ability of a compound to separate into ions
in solution
7
pH
  • pH the scale used to measure of how acidic or
    basic a solution is.
  • The name, pH, has been purported to come from a
    variety of places including pondus hydrogenii
    (Latin), potentiel hydrogène
    (French), and potential of hydrogen (English).

8
A pH value between 0 and 14 is used to indicate
the concentration of H or OH- in solution.
Mathematically, the pH of a solution is defined
as the negative common logarithm of the H
concentration pH -log H or H
10-pH Acidic solution pH lt 7 H gt 1.00 x
10-7 M Neutral solution pH 7 H 1.00 x
10-7 M Basic solution pH gt 7 H lt 1.00 x 10-7
M
9
Buffers
  • Buffer solutions are solutions which resist
    change in pH upon addition of small amounts of
    acid or base, or upon dilution.
  • The most commonly used buffers are weak acids or
    bases such as CH3COOH or Na3PO4.

10
Titration Curve
11
pH Indicators
12
pH meter
13
Using a pH meter
  • Remove probe from storage buffer
  • Place probe over rinse beaker, rinse with water,
    and dry probe with a kim wipe
  • Place probe in solution that is to be tested
  • Maintain constant stirring to evenly distribute
    the H ions in solution
  • When measurement is complete, repeat step 2 with
    the probe and return to storage buffer

14
Activity
  • Create a titration curve for a buffer of your
    choice using the pH meter
About PowerShow.com