Ideal Gas Law

The last lesson we learned the first week of the Gas Law unit was the Ideal Gas Law, which revolves around the Kinetic Theory of Gases. In this law...

1. "Gases consist of small particles (molecules) which are in continuous motion
2. "The volume of the molecules present is negligible compared to the total volume occupied by the gas"
3. "Intermolecular forces are negligible"
4. "Pressure is due to the gas molecules colliding with the walls of the container"

Real gases are different from ideal gases because there is less kinetic energy in real gases at low temperatures. So, they are able to attract each other at high pressures because they are closer together so that the volume of the gas molecules becomes significant compared to the volume the gas occupies. 

Below is the formula used for the Ideal Gas Law:

http://dl.clackamas.edu/ch105/lesson1ideal_gas_law.html

P=pressure, V=volume, n=moles, R= gas constant, T= temperature. The gas constant in 0.0821 L atm/ mol K

Here is a link that explains ideal gases more:
Ideal Gas Law

Avogadro's Law and Combined Gas Law

On Wednesday, we learned our third and fourth gas law. Avogadro's law states that volume is directly proportional to the number of moles of gas present as long as there is constant temperature and pressure. So, as the number of moles in a gas increase, the volume will have to increase to maintain that constant pressure and temperature. Here is a picture that represents that concept:

http://wps.prenhall.com/wps/media/objects/4678/4790892/ch09_02.htm

As you can see, the moles and volume doubled to keep the pressure at 1 atm in both cases.

Below is the formula we use in math problems that involve Avogadro's law:

http://me-mechanicalengineering.com/gas-laws/

A helpful fact that comes in handy with some math questions is that the volume of one mole of gas is 22.4 liters. This can be used as a conversion factor.

We also learned about the combined gas law that involves a change in all variables, like moles, volume, temperature, and pressure. It combines all of the gas laws we have learned so far. Here is the formula for it:

http://me-mechanicalengineering.com/gas-laws/

Here are also a couple links that further explain these two laws:

Combined Gas Law

Avogadro's Law

Charles' Law

The second law we learned in our gas laws unit was Charles' Law. In his law, he tells us that temperature and volume vary directly with each other. If the temperature increases in a gas, the volume will have to increase in order to keep the pressure constant because of the energized molecules. Here is a chart that exemplifies this:

http://agaul01.blogspot.com/2014/04/boyles-charles-law-in-relation-to.html

Here is his formula too. It is easy to plug in the information you get from a problem, but you have to make sure that you convert Celsius to Kelvin if the problem gives you a temperature in Celsius. :

https://www.clippard.com/cms/wiki/charless-law

Below are a couple links that explain Charles' law more and provide some practice math questions:

Chemteam

Practice Problems

First Lesson

Today in Chemistry, we learned our first Gas Laws Lesson. We focused on Boyle's Law, which only manipulates volume and pressure. It is an inverse relationship, and holds true at a constant temperature. Below is the formula:

http://www.physbot.co.uk/gas-laws.html

To represent its inverse relationship, take the picture below into account:

http://www.cyberphysics.co.uk/topics/kinetic_theory/boyle.htm

As you can see, as the volume decreases, the pressure increases, representing its inverse relationship.

Here are some more links that elaborate on Boyle's Gas Rule:

NASA

ChemTeam

Practice

2nd Lesson Practice

While studying for the unit test,  I found these links helpful, further explaining and offering practice on intermolecular and intramolecular forces and phase diagrams. I hope you find these helpful!

Phase Diagrams Quiz

Intermolecular and Intramolecular Force Practice

Phase Diagrams

Intermolecular and Intramolecular Forces

http://www.kentchemistry.com/links/Matter/Phasediagram.htm

Lab

Yesterday in class, we performed the Specific Heat Capacity of a Metal Lab. In this experiment, we had to place hotter pieces of copper at a certain temperature into a cup of cooler water at a certain temperature to find the heat capacity of the copper. To find the heat capacity, we plugged in all the data from the lab into the equation -MCAT=MCAT. Here are some pictures from the lab:

Here are also some links to practice similar equations:
KentChem
CBHS
Problem Solving With Heat

First Lesson

      Once we finished our Biodiesel projects, we began our next unit: Energy and Phase Diagrams. On Friday, we learned about energy changes and how they are due to the rearrangement of chemical bonds. Most people believe that energy is stored in chemical bonds. However, the "addition of energy is always a requirement for the breaking of bonds, but the breaking if bonds in itself, does not release energy. " "Whether or not an overall reaction releases or requires energy depends upon the final balance between the breaking and forming of chemical bonds." That's where we came to endothermic and exothermic reactions. In an endothermic reaction, energy is gained from the surroundings of the reaction. In an exothermic reaction, energy is lost to the reactions surroundings. Here are diagrams that displays this concept:

https://www.premedhq.com/endothermic-and-exothermic-reactions

http://pindex.com/b/ks3chemistry/energetics

In addition, we learned about calculating heat. To find heat or any of the other components in the equation, use the formula MCAT (M= mass, C= specific heat, AT=delta/temperature=change in temp)

http://www.wikihow.com/Calculate-Specific-Heat

Here are some other helpful links that further explain what we learned in the lesson:

Specific Heat

Endothermic and Exothermic Reactions

Temperature and Heat