THE LAB...

All right, everyone. I'm pretty sure everyone is pretty confused on what we are supposed to do for THE LAB, so I'm going to try and put out there what I think we are supposed to do. Scully, I'm counting on you especially to call me out for being wrong on anything.

Ok, I'll start off with some definitons:

1. titration-adding NaOH to KHP until it turns a "the lightest shade of pink"
2. KHP-potassium hydrogen phthalate; it's the stuff that look like big salt
3. NaOH-sodium hydroxide; it's what goes in the buret, and is located in a keg-thing by the microwaves
4. phenolphthalein-[fee-nawl-thal-een] stuff that is in X-lax (not the lacrosse possition!) it's what makes the titration, your mixture of NaOH and KHP turn pink

Next off, some general starter. I'll leave some stuff some other guys to comment though

1. --get 2, TWO, samples of KHP; keep it as close as you can to 0.50 g, but it's better to go lower
2. --dissolve KHP in a beaker of ionized water and 2, TWO, drops of pheolthinggummy; swirl it around until it is completely dissolved
3. --while one guy is doing step two, the other can use the tiny beaker Dr. B gave us, fill it with NaOH from the keg-thing, and pour it into the buret.
4. initial NaOH volume reading=0.something(measure from zero); record this before you titrate;
5. stick the beaker of dissolved KHP under the buret and open the valve. THIS IS YOU TITRATING
6. When you're titrating, let in 5 or so mL of NaOH, then swirl, let in another 5 and swirl, let in another 5 and swirl, AND THEN start adding it in drops sssslllooooowwlllllyyyyyyyy (you add it slowly because the point where it is "the faintest shade of pink" arrives really fast)
7. after you titrate, make your Final NaOH volume reading
8. Final NaOH volume reading= somewhere in the teens(measure from zero)

Now all you do is repeat the steps, except you don't have to necessarily add more NaOH. You can just go from where the last one was. You just have to take that into account in your volume readings.

Ok, I really hoped that helped some of you. If it didn't, well I went to St. Ann, you can't expect me to be that good.

AND IF YOU THINK I'M WRONG, FREAKIN' TELL ME. INFALLIBLE IS NOT ME. that guy's German, and is probably just waking up right now to celebrate some Jesus in Rome. If he isn't somewhere else in the world, but I digress.

goodnight!

4-28-10

Hey, everyone. I'm going to do a quick blog tonight because i want to go to bed early, and, well, we didn't have that much to do.

We worked on those worksheets while Scully and Dr. B were at their chemistry luncheon.

Everyone, make sure you have your pre-lab finished for tomorrow. We start the lab, and Dr. B said we will be working on it for a couple of days. I think the lab is kind of hard to understand, I mean it keeps throwing around words like titration and penolphthalein (I still have no idea how to pronounce that). Soooo, I read a couple of times, and it sunk in. I just hope that Dr. B runs through it a little tomorrow.

allllllllllllllllllllllllllll right, comment time!

4-27-10

hey wassup everybody here's what we did in class today and feel free to comment on anything I left out.

Indicators & pH meters

1. Transition interval

• the pit range over which an indicator changes color
• Indicators that change color at pH lower than 7 are stronger acids than other types of indicators
• Ionizes more than the others
• Indicators that undergo transition in higher pH range are weaker acids

2. pH meter

• determines the pH of a solution by measuring the voltage between the two electrodes that are placed in the solution
• voltage change as water ion concentration in the solution changes
• measures pH more precisely than indicators

3. Titration

• controlled addition and measurement of the amount of a solution of known concentration required to react completely with a measured amount of a solution of unknown concentration

Remember to finish up your pre-lab if you did

have a good night

4/26/10

Ch. 14 contd.

-Any species that can react as either an acid or base is described as amphoteric. A good exmple of this is water

-Water can act as a base
-Water can also act as an acid

-The covalently bonded OH group in an acid is referred to as a hydroxyl group.
-Molecular compounds containing OH groups can be acidic or amphoteric.
-The behavior of oxygen atoms bonded to the atom connected to the OH group.

-In aqueas solutions, neutralization is the reaction of hydronium ions and OH ions to form water molecules.

-A salt is an ionic compound composed of a cation from a base and an anion from an acid.

-NO, NO2, CO2, SO2, and SO3 gasses from industrial processes can dissolve in atmospheric water to produce acidic solutions.

-Very acidic rain is known as acid rain. Acid rain is not as rare as people might think. It is actually fairly common but it is normally not found in large concentrations

END OF CH 14. (Followed by DR. B's famous smile that we have grown to hate when ch's end...)

Ch. 15

-In the self-ionization of water, two water molecules produce a hydronium ion and a hydroxide ion by transfer of a proton.

-Solutions in which H3O=OH, its a neutral solution
-Solutions in which H3O>OH, its acidic
-Solutions in which H3O
-Strong acids and bases are considered completely ionized or dissociated in weak aquous solutions.

-The pH of a solution is defined as the negative of the common logorithm of the Hydrogen ion concentration.



There is a link on the HW website with the pre-lab Q's that are due tomorrow and Dr. B has asked us to bring in our Lab Books to class tomorrow. Have a good night.


-

Was there no Blog for this weekend? If there wasn't, well Friday all we did was watch a movie.
That is all.

Notes for Thursday, April 22, 2010

So, everybody has your tests in hand. Keep in mind that they will be graded out of 33, not 35, and there may be a chance for extra credit.

• An acid reacting with a base will produce a salt (not NaCl, although that is a type of salt) and water.
• The stronger an acid, the weaker its conjugate base.
• The stronger a base, the weaker its conjugate acid.
• Proton transfer reactions favor the production of the weaker acid and the weaker base.
• There are some conjugate acid-base pairs that we will need to know. There's a table, but since I don't have my book on hand, feel free to comment with the page in the book where it can be found.

Well, that was pleasantly brief. Good night everybody!

4/21/10

Today we had a test. It was over chapter 12 and 13. How did everyone do?

Notes for Monday, April 19, 2010

Test Wednesday, everybody! If you can't do molarity problems, molality problems, or problems on colligative properties, then start practicing. Feel free to comment with practice problems.

• A monoprotic acid is an acid that can donate only one proton.
• A polyprotic acid can donate more than one proton per molecule.
• A diprotic acid can donate to protons per molecules, and a triprotic acid can donate three protons per molecule.
• A Lewis acid is an atom, ion, or molecule that accepts one electron pair to form a covalent bon. This is the broadest of the three acid definitions. A bare proton is a Lewis acid. This is the only definition that is not based on hydrogen. A silver ion can be a Lewis acid, for instance.

Here's a table for remembering the different definitions of acid.

-	Acid	Base
Arrhenius	H, H3O producer	OH producer
Bronsted-Lowry	proton donor	proton acceptor
Lewis	electron-pair acceptor	electron-pair donor

• The species that remains after a Bronsted-Lowry acid has given up its proton is the conjugate base of that acidd.
• Bronsted-Lowry acid-base reactions involve 2 acid-base pairs, known as conjugate acid-base pairs.

And no, I don't have a clue why Blogger put a giant gap before the table.

4/16/10

Today, Dr. Bautista was not here. We watched a movie on Mars. It was very interesting and showed the time and dedication of the teams operating the rovers. Very soon we will know more about Mars.

Chemistry Notes for Thursday, 4/15

In class we discussed how Dr. B checked and graded the R constant labs. I however, do not have those notes, and leave it to you guys to fill that part in.
CLASS NOTES:
- Arrhenius Acids are molecular compounds with ionizable hydrogen atoms
-Their water solutions are known as aqueous acids
-All aqueous acids are elctrolytes
- A strong acid ionizes completely in aqueous solutions.
-Strong acids are strong electrolytes
Ex: HClO4 HCl, HNO3

-A weak acid relaes few ions in aqueous solutions
- Hydronium ions, anions, and dissolved acid molecules in aqueous solutions
Ex: HCN
-organic acids (____COOH molecules), such as acetic acid are weak acids

-Most bases are inoic compounds containing metal cations and the OH- anion
-Ammonia, NH3, is molecular
-Ammonia produces OH- ions when it reacs with water molecules
-The strength of a base depends on the extent in which it dissociates in a solution
-Strong bases --> Strong electrolytes
Amount of H3O+'s to OH-'s in types of solutions
Acidic
H3O+ > 10^-7 Moles >OH-
Nuetral
H3O+ = 10^-7 Moles = OH-
Basic
H3O+ < 10^-7 Moles< OH-

Bronsted Lowry Acids and Bases
- A Bronsted Lowry-Acid is a molecule or ion that is a proton donor
-HCl acts as a Bronsted-Lowry acid when it reacts with ammonia
-Water can act as a Bronsted-Lowry Acid
-A Bronsted-Lowry Base is a molecule or ion that Acts as a proton acceptor
-Ammonia accepts a proton from HCl, and is therefore and Bronsted-Lowry Base
- the OH- ion produced in solutions by acids is a Bronsted-Lowry Base

- In a Bronsted-Lowry Acid-Base reaction, protons are transferred from one reactant(the acid) to another (the base)

The blog by chris mathews

today we talked about acids, but not before we went over some very challenging chemistry questions. Good news of the day is that kyle "Half Caff McCaffery" (if i spelled it wrong please correct me) was moved and now gets to sit with us in the front

back to the notes

first acids are aqueous solutions that usually have a sour taste, they can change the color of an acid-base indicator, react with active metals to release H2 gases, react with bases to produce water and salts, and finally conduct electricity.

binary acid- acid that contains only two elements, one of which has to be hydrogen and the other and electronegative element.

examples are HF HCl HBr

the name starts with -hydro for the hydrogen element

then to the root of the second element comes into play

finally all of this is followed by an "ic"

ex. HF is know as hydrofluoric acid notice the suffix and prefix usage

next we have the oxyacid-is an acid that is a compound of oxygen, hydrogen, and usually a nonmetal. these names also follow a pattern

names of anion are based on the names of the acid. next if the anion ends in ate it is an "ic" ending but if the anion ends with ite its ending is "us"

now we have sulfuric acid

apparantly its one of the most commonly produced industrial chemicals in the world, but dont clean the container holding it, or it will corrode!!!

nitric acid, phosphoric acid had no definitions...

hydrochloric acid- concentrated solutions of this acid are commonly called muriatic acid

acetic acid-pure acetic acid is clear, colorless, and pungent smelling liquid that is also known as

glacial acetic acid

i do believe this is the point in class where colby maybry made the brilliant oration on the different levels of acid strength, all of which are related to disassociation.

bases

they taste bitter, change with acid base test, dilute solutions feel slippery, react with acids to produce water and salt, and conduct electricity.

this is all i got for the day. Thank you and have a wonderful evening

ps quiz tomorrow over ch 13 calculations, this should be a good way to bring those averages up guys and remember that the test will be next thursday.

-Electrolytes & Colligative Properties cont'd.

-the actual values of the colligative properties for all strong electrolytes are almost always what would be expected based on the number of particles they produce in solution

-the differences are caused by attractive forces between dissociated ions in aqueuous solution

-according to Debye & Huckel, a cluster of hydrated ions acts as a single ion rather than as individual ions, causing effective total concentration to be less

-Ions of higher charge have lower effective concentrationss than ions with smaller charge

Multiple Choice

1. Acetic acid is a weak electrolyte because it

D. ionizes only slightly in aqueuous solution

2. Which of the following solutions would contain the highest concentration of hydronium ions?

A. 0.10 M HCl

3. Which of the following is the best representation of the precipitation reaction that occurs when aqueuous solutions of sodium carbonate and calcium chloride are mixed?

C. CO3(2-) (aq) + Ca(2-) --> CaCO3(s)

4. Which of the following is not a colligative property?

A. molality

5. Solution A contains 0.1 mol of sucrose, C12H22O11, dissolved in 5oo g of water. Solution B contains 0.1 mol of sodium chloride, NaCl, in 500 g of water. Which of the following is true?

C. Solution A would freeze at a higher temperature than Solution B would.

colligative properties of solutions

colligative properties

• Properties that depend on the concentration of solute particles but not on their identity

the boliing point of a solution differ from those of the pure solvent

nonvolatile substance

• substance that has little tendency to become a gas under existing conditions

nonelectrolyte solutions of the same molality have the same conecntration of partilces.

freezing-point depression

• the freezing-point depressino of a 1 m solution of any nonelectrolyte solute in water is found by experiment to be 1.86 degrees Celsius lower than the freezing point of water.

molal freezing-point constant

• the freezing point depresino of the solvent in a 1-molal solutino of a nonvolatile, noneletrolyte solute

freezing point depression

• the difference between the freezing points of the pure solvent and a solution of a nonelectrolyte in that solvent, and it is directly proportional to the molal concentration of the solution

Ksub f is expressed as degrees Celsius/m

each solvent has its own characteristic molal freezing point constant

boiling point elevation

• the boiling point of a liquid is the temperature at which the vapor pressure of the liquid is equal to the prevailing atmospheric pressure
• a change in the vapor pressure of the liquid will cause a corresponding change in the boiling point

molal boiling point constant

• the boiling point elevation of the solvent in a 1-molal solution of a nonvolatile, nonelectrolyte solute.
• the boiling point elevation of a 1-molal solution of any nonelectrolyte solute in water has been found by experiment to be 0.51 degrees C

boiling point elevation

• the difference between the boiling points of the pure solvent and a noneletrolyte solution of that solvent, and is directly proportional to the molal concentration of the solution
• change in temperature = (constant of temperature) (m)

osmotic pressure

• the external pressure that must be applied to stop osmosis

osmosis

• the movement of solvent through a semipremeable membrane from the side of lower solute concentration to the side of higher concentration

semipermeable membrane

• membrane that allows the passage of some particles while blocking the passage of others

Weekend Blog

Strong electrolyte - compound in an aqueous solution that conduct electricity well/many ions/strong acids contain strong electrolytes

Weak electrolyte - poor conductors of electricity/ very few dissolved ions/ no ionic compounds

Colligative properties - depend on concentration of solution

Vapor-Pressure Lowering

Freezing-Point Depression

Boiling-Point Elevation

Osmotic Pressure

Nonvolatile substance- substance with little tendency to become gas

In nonvolatile substances Boiling-Point rises Freezing-Point lowers

the blog

nobody blogged so i decided to do it anyways.

today we took the pop quiz that everyone failed including top ten chem student in shelby county michael scully (congrats on the award we know the quiz was a fluke). also the answers to all the homework problems were put on the board and everyone copied them down. if you have any issues use the email and be ready for any more disastrous quizzes in the future.

4.7.10.

Sorry the blog took so long to get up, the rain and everything messed with my computer and it kept crashing on me. But here you go.

The seperation of ions that occurs when an ionic compound dissolves is dissociation.
see book for example equations.
review book pg 436 example problem A.

Although no ionic compound is completely insoluble, compounds of very low solubility can be considered insoluble for most practical purposes.

GENERAL SOLUBILITY GUIDELINES -
1. Sodium, potassium, and ammonium compounds are soluble in water.
2. Nitrates, acetates, and chlorates are soluble.
3. Most chlorides are soluble, except those of silver, mercury (I), and lead. Lead(II) chloride is soluble in hot water.
4. Most sulfates are soluble, except those of barium, strontium, lead, calcium, and mercury.
5. Most carbonates, phosphates, and silicates are insoluble, except those of sodium, potassium, and ammonium.
6. Most sulfides are insoluble, except those of calcium, strontium, sodium, potassium, and ammonium.

NOTE:
To decide whether a precipitate can form, you must know the solubilities of those two compounds.

Net Ionic Equation -
includes only those compounds and ions that undergo a chemical change in a reaction in an aqueous solution.
see book pg 439 for example equation.

Spectator Ions -
ions that do not take part in a chemical reaction and are found in solution both before and after the reaction.
see book pg 439 for example equation.

review example problem B, pg 440.

ionization -
ions are formed from solute molecules by the action of the solvent in a process called ionization.

When a molecular compound dissolves and ionizes in a polar solvent, ions are formed where none existed in the undissolved compound.

Hydrogen chlorie, HCl, is a molecular compound that ionizes in aqueous solutions. It contains a highly polar bond. The attraction between a polar HCl molecule and the polar water molecules is strong enough to break the HCl bond, forming hydrogen ions and chloride ions.
see book pg 441 for example equation.

The Hydronium Ion -
some compounds ionize in an aqueous solution to release H+. The H+ ion attracts other molecules or ions so strongly that it does not normally exist alone.
see book for example equation pg 441.

The H3O+ ion is known as the hydronium ion.

Substances that yield ions and conduct an electric current in solution are electrolytes.
Substances that do not yield ions and do not conduct an electric current in solutions are non-electrolytes.

Strong Electrolyte-
is any compound whose dilute aqueous soltions conduct electricity well; this is due to the presence of all or almost all of the dissolved compound in the form of ions.

Weak Electrolyte -
is any compound whose dilute aqueous solutions conduct electricity poorly; this is due to the presence of a small amount of the dissolved compound in the form of ions.

STRONG AND WEAK ELECTROLYTES DIFFER IN **THE DEGREE OF IONIZATION OR DISSOCIATION.**

Have a good night guys.
Colby & Co.

Tuesday, April 6

Today in Dr. B's class we handed in our homework whch was #7-15 (additional problems). Dr. B then handed back the test on chapter 10 & 11, the test is out of thirty (27 on the scantron, 3 written answers). After we looked over the test Dr.B assigned the rest of the additional problems for homework. Thats pretty much it.