I hate life

So I was almost done, and the autosave thing said it was saved, so when I had to go, I just closed it. And it didn't save. So I have to restart. yea. life sucks.

The beginning of chem was fun, because we watched Steven Colbert singing "Friday" for some fundraising thing. And then we talked about weird stuff like farms.

But then we learned. Like scientifical stuff.

First was equilbrium. Basically it occurs when a reaction is going forward at the same rate its reverse reaction is going. So if we have a reaction A --> B, we would reach equilibrium if A's were changing into B's at the same rate that B's were changing into A's. Thus we can determine, that once we reach equilibrium, the total number of A's and B's, or their concentration, will not change, though they may not necessarily be equal.

Ok. so that was easy.

This part is shaky for me.

So for the equation: aA + bB < - > cC + dD, where the little letters are coefficients and the big letters are gases, we can get this equation:

Ok, so that's kinda not really simple. why is my font bigger. Ok, now it's too small. That bothers me.

So the PA-D 's represent the pressures of each of the gases. Then they are raised to the power of their respective coefficients. And from there it's pretty straight forward.

We also get this other equation:

Kc = [C]^c[D]^d/[A]^a[B]^b

The brackets here around the letters mean "the concentration of". So [C] means the concentration of gas C. It is essentially the same equation as before, only we use concentration instead of pressure.

Now we have an equilibrium pressure constant, and an equilibrium concentration constant, so now we relate them with yet another equation.

Kp = Kc(RT)^∆n

These should be familiar, we have the constants and the universal gas constant (.0821 L*atm/mol*K) and the change in moles of gas.

I am pretty sure the moles referred to is the total number of moles (moles of products - moles of reactants) but I could be wrong).

We have a WA due tomorrow. So get some sleep. and do it during lunch. and watch this:

normality

Umm scribing tomorrow will be.. MOLLIE McAWESOME

The Ninja From Down Under

Today we had shortened classes and Mr. Liberman was not there. So, we had a sub and we got to watch Myth Busters! SWEAAAAAAAAAAAAT! This episode was the second one they have done on ninjas. They were retesting if a ninja could actually catch an arrow, but this time they had the most accomplished ninja in the world today who happened to be Australian. Adam and Jamie the two hosts talked about how that the speed of an arrow does not change on release from the bow to impact with its target. The first experiment was to see if the ninja could catch tennis balls going 80 mph's and he caught 22 in a row a Guiness World Record. Then Jamie tried to accomplish this feat thinking it was being overplayed he was soon pelted relentlessly with thennis balls quite amusing. Next, Carry, Grant, and Tory tested the old assination technic that ninjas would lay in wait in river banks breathing out their blow guns and then using them to kill their target. First they checked how long Tory could stay underwater with out suffering hypothermia and he felt he could last about an hour. Next they tested if they used an all natural blow gun how their aim would be. Tory and Grant made all natural ones but they accuracy was pitiful. Next, Carry who cheated by putting a metal rod in had perfect accuracy. Next she sat underwater and had to deal with the refraction of the water to hit the target. Eventually she go the hang of it. Next they tried to put all the aspects together breathing through it, being cold, and having to transfer the dart in. The myth was busted because no one could load the dart without shooting it with water. Back to Jamie and Adam they put their ninja to the test when he caught an arrow then they put him between three archers and at first he could not do it. Eventually when they moved back and the one who had to shoot had to draw his bow the ninja caught it. The next segment was supposed to be the one inch punch but we did not get to it. Thats it the next scrib is Matt Park

The Slimy Blue But Also Clear Stuff Lab

Hiiiii guys! Alright so if you were sick today (Colleen) you missed out on another wonderful lab. The point of this lab was to figure out the different factors that affect reaction rates. Sadly, this lab was incredibly long and we did not have time to finish it today, but my group did make it through part one..or A, whatever you want to call it.

This part of the lab was testing the effect of temperature on reaction rates, and the reaction we were observing was between the slimy blue solution and oxygen. When the solution reacts with oxygen, it turns clear, when it is not reacting with oxygen it is blue.

By shaking the solution in the pipette, we were re-oxidizing the solution and caused the methylene blue color to appear. Once the solution was put to rest, it settled and the glucose in it reduced and it became clear again. This reaction time was measured at four different temperatures (in degrees Celsius ) : 10, 20, 30, and 40. My group's data looked like this:

Using this, we concluded that as temperature increased, the rate of reaction increased as well (which you might notice is the CLAIM part of your conclusion, you're welcome.) So, that was basically what we did today, we are going to finish the second part of the lab tomorrow. And the lucky person who gets to write about that is......Brandon L! Have fun Brando!

Colliding into Activation Energy

By: Emilio I. April 4th was the first day back from Spring Break so we began a new unit, unit 11: Kinetics and Equilibrium. We started off by talking about the collision theory and how a chemical reaction can not occur if the reactions do not collide. Mr. Lieberman used the example that if two substances are on opposite sides of a container, they cannot react at all! This is true because when molecules collide they transfer kinetic energy and break the bonds that hold other molecules together.

Kinetic energy is half the battle, the other half is having correct orientation. In order for a reaction to occur between molecules, specific atoms must crash into eachother at specific speeds. Here is an image describing the idea behind orientation and chemical reactions:

The Kinetic energy required to break the bonds in a molecule and cause a chemical reaction is known as the Activation Energy. It is also referred to as the Activated Complex. It is at the top of the graph showing a reaction's energy, just like this one: We only discussed one way to increase the speed of this type of reaction, although there are many ways to do this. The one we discussed is by adding a catalyst that lowers the activation energy which allows a higher number of reactions to occur among the molecules in the reaction. The catalyst is not a part of the reaction, though, so it will not appear in the reactants or products. The next Scribe will beeeeee: Kaitlin S. Goodluck

Colligative Properties Lab

Today in Chemistry we did the Colligative Properties Lab. The goal of this lab was to use boiling point elevation data to identify an unknown salt. We began by labeling four 100 mL beakers A,B,C, and D and recording their masses in our super neat data tables. Next we filled each of the beakers about half full with distilled water. We recorded the mass of the beaker and water in our data table. We then placed the beakers full of water on the hot plate and heated them to about 85°C at which point we removed them from the hot plate. We determined the boiling point of the water in beaker A by noting the plateau on our lab pro. We recorded this number and proceeded to add about 5.0 grams of the unknown ionic solid to beaker B. We placed it on the hot plate and recorded its boiling point in our data table. We then added about 10.0 grams of the unknown solid to beaker C. We placed it on the hot plate and recorded its boiling point once again. Finally we added 15.0 grams of the unknown solid to beaker D, placed it on the hot plate, and recorded its boiling point in our data tables.

As a part of the data/calculations we were asked to calculate the molality of each solution and were given the molal boiling point elevation constant: 0.51°C kg/mol. To calculate the molality of each solution, we used the equation ΔT_b = K_b · m · i. To calculate change in temperature, we subtracted the boiling point of beaker A from beaker B, beaker B from beaker C and so on. We were told the ionic sold has 2 ions, so i=2. We plugged these values into the equation and solved for m to get a value for molality.

To calculate the moles of solute in beakers B, C, and D, we used the molality equation which says that molality = mol solute / kg solvent. We have the value for molality and to find the kg of solvent we simply subtracted the mass of the beaker from the mass of the beaker and water and divided the answer by 1000 to obtain the value in kilograms. To find the moles of solute, we multiplied the molality by kg solvent.

To find the molar mass of the solute in beakers B,C, and D we divided the number of grams of solute in each mixture by the moles of solute obtained in the previous step. We added 5.0 grams to beaker B, 10.0 grams to beaker C, and 15.0 grams to beaker D. These values were divided by the moles solute to obtain the molar mass of the solutes. To calculate the average of the molar masses, we just added them together and divided by three.

The conclusion asks you to decide the formula for the unknown solute, so choose the formula with the molar mass closest to your average. The choices are NaCl, KI, NaNO3 or NaBr. Support your claim with evidence and then calculate the percent error:

| actual value – theoretical value | x 100 %
theoretical value

The lab is due Friday and so are all of the worksheets and Webassigns. Study for the Test Friday!

The next scribe will be Emilio I!