Sunday, February 28, 2016

Acid Base Unit Test reflection

This unit test didn't go as well as I expected it to go. On the quiz for this unit I did very well, and I thought that I was well prepared for this test. The things I think I messed up on were the ice box problems and some of the problems that were mostly definition. All in all the unit was not too bad, I just wish that I could have done better on the test.

Here are some things i used to study.
http://chemwiki.ucdavis.edu/Core/Physical_Chemistry/Equilibria/Le_Chatelier's_Principle/Ice_Tables

http://chemwiki.ucdavis.edu/Core/Physical_Chemistry/Acids_and_Bases/Acid%2F%2FBase_Reactions/Conjugate_Acids-base_Pairs

https://www.khanacademy.org/science/chemistry/acids-and-bases-topic/copy-of-acid-base-equilibria/v/conjugate-acids-and-bases

http://chemed.chem.purdue.edu/genchem/topicreview/bp/ch11/conjugat.php

pH and pOH conversion square

To determine the pH of a solution or the pOH of a solution, we need to know the (H+) concentration or the (OH-) concentration. Using these we can calculate the pH, pOH, and the H+ if given the OH-, and the OH- if given the H+.

Here is the square that we use to go from one concentration to another.
Image result for ph poh conversion square
http://www.fullerchemistry.com/Acid-Base%20Chemistry/acid.htm

The H+ Ion in water

The H+ ion is simply a proton (nucleus of a hydrogen atom without its valence electron)

  • In water, clusters of hydrated H+ ions form
  • The simplest cluster is H3O+
  • we call this the hydronim ion
  • Larger clusters are also possible (such as H5O2 and H9O4)
Generally we use H+ and H3O+ interchangeably


Bronsted-Lowery Acids and Bases


  • Bronsted-Lowery acids donate a proton (H+) 
  • Bronsted-Lowery bases accept a proton (H+)

In the B.L. definitions, we have conjugate acid and conjugate bases. These come in pairs.
Acids produce conjugate bases and bases produce conjugate acids

  • Conjugate acid: the substance formed when a proton is added to a base
  • Conjugate base: the remaining substance when a proton is lost from an acid

Image result for acid base conjugate
http://tanmayonrun.blogspot.com/2011/10/what-do-you-mean-by-conjugate-acid-base.html

Acid and Base basics

Acids and bases have distinct physical properties

  • Acids:taste sour and feel sticky
  • Bases:taste bitter and feel slippery
  • There are several different definitions of acids and bases and it is important to distinguish between them all
  • Bases=7.1-14
  • acids=1-6.9
  • Arrhenius acids are those species that produce hydrogen ions in solution
  • Arrhenius bases are those species that produce hydroxide ions in solution
pH Scale

http://www.chem4kids.com/files/react_acidbase.html

Percent Acetic Acid in Vnegar Lab

In this lab, we standardized a solution of NaOH with potassium hydrogen phthalate in a titration to determine the molarity of NaOH solution. We then used this standard NaOH solution to determine the % acetic acid in commercial vinegar.

Here were the steps to the titration.\

http://www.sparknotes.com/chemistry/acidsbases/titrations/section1.rhtml

  1. Put on splash proof safety glasses
  2. drain buret into the waste beaker
  3. rinse your buret with a small amount of NaOH
  4. with the valve closed, add NaOH until it is above the zero mark
  5. Obtain 0.5-0.8 g of KHP
  6. transfer KHO into Erlenmeyer flask
  7. add 75ml of water to flask
  8. add 2-3 drops of Phenolphthalein
  9. open vial with blue cap
  10. pipet 10ml of vinegar into flask
  11. drain buret, fill with distilled water