The following Chem Talk is called Thermodynamics. I learned that some reactions can continue to occur on its own once it begins and that this reaction is called spontaneous. This made total sense because of the meaning of the word when it is not related to chemistry. Thermodynamics and Kinetics are both theories that predict when it will occur spontaneously and how is can speed up and slow down. When a energy change; however, occurs at a constant pressure, chemists call this “change in enthalpy.” If the change is negative the reaction is exothermic and if the change is positive then the change is endothermic. The bump is the height of the reactant energy. This is called the activation energy and is always positive. The top part, which is the state in-between the reactants and products is called the activated complex. The last interesting thing I learned was about the catalyst, which is a substance that speeds up a chemical reaction without being used up itself. For example, anything with more surface area makes the reaction faster and also iron is one in a reaction between magnesium and water. This was a very information filled chem talk and I was a bit confused, but we will see what happens during the lab when its all cleared up.
This chem talk was not very long but I managed to learn that some solutions are capable of conducting electricity and some of the particles with it.
3. a. Al
4. The pair Al and Pb
(Al -> Al3+ + 3e-) x2
(Pb2+ + 2e- -> Pb) x3
2Al + 3Pb2+ -> 2Al3+ + 3Pb
7. c.) the same
8. b.) Zn(s) –> Zn2+(aq) + 2e-
9. d.) loses an electron
10. b.) electrons will go from Cr3+ to Al
In this chem talk I learnt a few new things. It taught me about properties of metals and what they are capable of when they are met with outside forces. The chem talk spoke about alchemists. I had heard of the name before but never knew what exactly they did. They discovered some metals react more easily with most metal ion solutions than other metals do. Another new aspect I read about was oxidation- reduction reactions. I had heard the word oxidation before, either throughout my day or earlier in the year. However, what I did know was that it had to do with electrons. They also call these reactions “half reactions.” It is smart that they call these reactions half-reactions because both sides react and based on how many electrons you give away, you will get that many electrons back by the other element. Some metals might not be a metal and a example of this is hydrogen. Hydrogen has no properties of a metal but it takes on the positive nature of a metal in strong acids. An example of this would be hydrochloric, which is HCl vs. NaCl. This chem talk brought back familiar faces, and even helped me learn new things. It was very interesting and I am ready to see what is in store for us in class.
Balancing chemical Equations is very interesting and at first was a difficult concept to master. However, with practice in class and while doing homework it became easier. The law of conservation is the amount of matter present before and after a chemical change stays the same. Even though the same amount of each element must enter and exit with the same amount. Recently in class we have been talking about intermolecular forces, to be specific the bonds that make up those forces. Learning about the different kinds of intermolecular forces is very interesting since there are so many kinds of bonds with varying strengths and energy levels. The stronger the intermolecular force the higher the boiling point the weaker it is the lower the boiling point is. The strongest of the bonds is ion-ion with an energy of 800 and London dispersion forces with the lowest energy of 10.
The beginning of this section started off as a bit of a review session. It began talking about moles and molar mass, which was a great refresher. One of the most important thing to know about moles is that one mole of any atom or molecule is equivalent to its molar mass in grams. The Chem talk spoke about balancing equations and incorporated moles into it. When it comes to balancing equations, I knew what it was talking about, but when they added moles it began to get tricky Basically all the talk is saying is that one mole of gas in room temperature will occupy more space than when it is in proper temperature conditions. Stoichiometry seemed to be a little confusing. I still don’t have a full grasp of the material, but this is just the first assignment and we’re yet to see what will happen in class.
There were also somethings that was introduced for the first time to me. This was called Intermolecular forces vs./and kinetic molecular motion. This was called Intermolecular forces vs./and kinetic molecular motion. The forces was the relation between the number and position of the electrons. The kinetic energy overcame the forces when heat was added and the next state of matter took place. The energy got greater when heat was added. This is just like ice, steam and water. When the ice melts into water and can be boiled and turned into steam. The ice freezes then heat is added and energy overcomes some force, then turns into water and heat is added and energy does its magic, and lastly it is steam. A new term I learned was nonpolar molecules which have shapes and bonds that are symmetrical. Something I found that was fascinating to me was when the size of the nonpolar molecule increased, the attractive forces between the molecules also begin to increase.