Slam a revolving door

Chuck Norris can slam a revolving door
Besides from the obvious... today in class, first thing we did was review the forces. We reviewed the dispersion forces, dipole forces, and hydrogen bonding. for more information you can look below at Elim's post.
After our review, we started our lab.
This lab has 7 stations to observe trends and patterns in several properties of liquids and to use a model of intermolecular forces to explain the findings.

Station 1: Evaporation Rates
This station measured the rate at which the liquid evaporated. the rate that the liquid evaporates depends on the strength of the intermolecular forces between liquid molecules. liquids with the lowest evaporation rates have the strongest intermolecular forces.
Insert Photo here that I could not find

Station 2: Capillary Action
A liquid tends to climb up the walls of narrow columns, this is known as capillary action. This is based upon two forces: adhesive forces, and cohesive forces. The greater the cohesive strength, the more the liquid climbs the column. The greater the adhesive strength, the lesser the liquid climbs the column.

Station 3: Vortex Formation and Relaxation
If you swirl water, you get a water tornado. That's what this is, just making vortex's by swirling the liquids. The time it takes for a liquid to settle down from a swirl is different for all liquids depending on the intermolecular forces. the longer it takes to relax, the stronger the intermolecular forces are. We did this with three liquids: Water, Hexane, and Heavy oil.

Station 4: Viscosity or Resistance to Flow
Not every liquid flows at the same rate (compare water to waffle syrup). Viscosity is the property of a liquid which provides a measure of that liquids tendency to resist flow. Liquids with stronger intermolecular forces have a greater resistance to flow, a higher viscosity. We took the same three substances as station 3, and put them in test tubes. After that we timed the seconds of a marble falling to the bottom of the test tube. The faster it is, the lower the liquids tendency to resist flow, or the lower the Viscosity. The lower the viscosity, the weaker the intermolecular forces.

Station 5: Surface Tension
Molecules on the very surface of a liquid can form strong enough intermolecular forces between them to make their surface impenetrable. It's this surface tension (along with other factors) that make leaves floar on water. For this expirement, we had to lower a paperclip using a tray to try to make it float on the liquid. The liquid that the paperclip can most easily float has the greatest surface tension.

Station 6: Beading
Many liquids have a tendency to bead. For example water droplets that look circular, that is actually the water beading. This is cause by liquid molecules to form a strong intermolecular attraction with itself and curl into a spherical bead or droplet. The greater the strength of the intermolecular forces, the greater the tendency of the liquid to bead. If placed on a surface the liquid is attracted to, the liquids beads less. For this expirement we dropped droplets of liquids onto wax paper and our lab benches. We then made observations according to what beaded and what didnt.

Station 7: Freezing point and Boiling Point
unlike the other stations, this one was all on our packet. all liquids have a freezing and boiling point. These points depend on the strength of the intermolecular forces. Liquids with stronger intermolecular forces have higher boiling points. The graph on our paper is pretty straightforward if you just remember that.


Don't forget we have a ton of webassigns due on Friday as well as this lab.
This lab must also have a conclusion on a seperate piece of paper (though the data can all be in the packet).
The next scribe will be Emilio.

Today, we did more practice in stoiceometry with limiting factors. We had the equation "Al + CuCl(2) --> AlCl(3) + Cu". First we had to balance the equation, so we got "2Al + 3CuCl(2) --> 2AlCl(3) + 3Cu". Now that we had the mole ratio, we could figure out which is our limiting reactant with the information of .82g Al and .87g CuCl(2).

To find out which one is the limiting reactant, there are two ways.
The first way, you could find out how much of one reactant you need to react with the other. We used Al for this one. So we take the mass, .82g Al, multiply it by 1 mole over it's molar mass, then find the mole ratio of Al and CuCl(2) (which is 2 to 3), then multiply it by the molar mass of CuCl(2). Since the answer (6.1g CuCl(2) was more than what we have (.87g CuCl(2)), we can conclude that CuCl(2) is our limiting reactant. If out answer turned out to be less than .87g, Al would be our limiting reactant.

The other method is to find out how much of each reactant you need to produce one product. It's always good to look ahead since this question 99.2% of the time will be right after the first: how much of a product you could make. You would follow all of the above steps for each of the reactants and you would choose a product. We used Cu as our finishing product. Remember, whichever reactant produces the least of a product is the limiting reactant. In the end, CuCl(2) produced the least Cu, which turned out to be .41g. Since that's the most that CuCl(2) can produce, that is all that will be produced. You don't do anything with that number!

So after we react this all, how much Al is left? well... to find that there are two ways you could do it, but both are pretty much the same.
First you could take how much of the limiting reactant you have and find out how much of the excess reactant you need to react it, which then you subtract that from how much you start with. To get this, just follow the steps listed in paragraph 2, except for the limiting reactant.

The other way is to take that .41g Cu and see how much of that excess reactant (Al) you need to react with that. It's basically all the same as listed above with different variables.

After we got through all of that, we got to our worksheet, Limiting Reactants, which is part of our homework.
For tomorrow, We need to have our Lab which we recently did and our chemistry question set #1.
1 silver troy ounce = $27.46, I got part of your homework done.
If you're still reading, please come up to me tomorrow and give me a waffle.
We will most likely have a quiz tomorrow, we were lucky not to have one today.


The next scribe will be... Austin W.

Insert Mole Title Here

So first off, I'd like to congratulate Kaitlyn on a wondeful posting job.
Now for class, we had kind of a work day in store for us. We got more practice with moles so we could better understand what it is and also we got more practice with unit conversion.
First off, we went to our notes and finished two "Learning Check!". First problem we had was:
Question: How many atoms of K are present in 78.4 g of K?
Work: Take the amount (78.4 g), multiply it by (1 mole of K over 39 (molar mass) grams of K), then multiply that by (Avogadro's number (6.02 times 10^23) over 1 mole of K).
Answer: 1.21 times 10^24.

Our second Learning Check! was:
Question: What is the mass (in grams) of 1.20 X 10^24 molecules of glucose (C6H12O6)?
So this question is actually working the opposite way of our other problem. We've got to find the mass (instead of molecules) and we start with the molecules (instead of the mass).
Work: 1.20 X 10^24 times (1 mole of glucose divided by Avogadro's number) times (the Molar mass divided by 1 mole of glucose).
To find the molar mass for this problem, we must take all the subscripts, multiply them by the mass of their individual atomic masses, then add all of those together. In this problem, the molar mass would be:
6 (subscript of Carbon) X 12 (atomic mass of Carbon) + 12 (hydrogen) X 1 + 6(oxygen) X 16 = 180 grams
Once we plug in the molar mass, our answer should be 359 grams per mole.

So, in order to really understand how we got this, you must already know about moles and molar mass. If you do not understand these fully, please either look back at your notes (you can find extras in moodle), or just look below at Kaitlyn's post.

After we finished those two problems, we had the rest of the period to work on our mole workshop. This compromised of 5 questions all of which we should have done by tomorrow with our partner. An extra copy of this worksheet can also be found in moodle under unit three worksheets (unfortunately the answers are not there).

Homework: Finish the Mole Workshop as well as the second mole worksheet. Both were given out before class.
Important dates: 10/20 (tomorrow!) review quiz on unit conversion and moles.
10/28 Unit exam, remember to have your homework problems done

Random fact of the day: Black whales are born white.
Also, I'd like to point out we had our first visitor from Japan.

Next Scribe will be Elim J