Monday, December 13, 2010

12/13/10

Announcements: Study for test on Thursday.

Homework: chem packet (due Wednesday) , and finish double replacement lab

Today in class we worked on the Double Replacement Lab in class. Mr. Paek explained how to mix the elements to see if there would be no reaction or a reaction. To do the lab you need to set up a data table that shows all the chemicals. Like this.



Then you mix each chemical once with the ones on the the grid and mark an which ones have a reaction, if there is no reaction write NR.

Next scriber: Mike A.


Wednesday, December 8, 2010

12/8/10

Announcements: do your homework and study! Quiz tomorrow!
Homework: Complete chemthink tutorial and quesitons (chemical reactions)!

On this day (late arrival) we learned about different reaction types:

1) Single Replacement
2) Double Replacement
3) Synthesis
4) Combustion
5) Decomposition

During single replacement, one element replaces another element in a compound. This kind of reaction consists of three elements: AX+Y. In this case A and X attract because they have the opposite charges (+ and -) while Y has a possitive charge. During single replacement, the product will end up being AY+X because now element Y has replaced element X. Example:

Since both copper and iron have a positive charge, they switch.

During double replacement, the positive charged elements and the negative charged elements switch places. This kind of reaction contains 4 elements: AB+XY. In this case A and X have positive charges and B and Y have negative charges. During the reaction, these elements switch pairs: AY+XB. To make it simpler, here is another example. There are two couples: AB and XY. A(boy) decides he doesn't like B(girl) and starts dating Y, and vice versa. Another example:


During synthesis, a 2 elements join together to form a complex compound. This reaction type is much easier to learn. An example: A+B=AB.

During decomposition, a complex compound seperates into two elements. Its the exact opposite of synthesis. An example: AB=A+B

Combustion is the reaciton of oxygen gas with anything. Combustion always and only contains oxygen carbon and hydrogen. It is the easiest reaction to learn because the answer is always CO2 + H2O. After this, all you have to do is balance the equation. Example:

Next scriber... IS PEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEETER I.

Tuesday, December 7, 2010

12/06/2010

Announcements: We will have two quizzes, none will be dropped. Homework will be assigned.

Homework: None


In class we learned about chemical reactions, and how to solve them. We started the day with atom counting. In atom counting, you have a formula and you count how many of each element there are. Ex. (2C+2O) There are 2 carbons and 2 oxygens in this formula.


Also we studied reactions and how they look. Ex. (N2+O2) the diagram would have both nitrogens attached to each other while the two oxygens will be attched to each other. The reaction is that both nitrogen and oxygen split and go to the opposite. the final balanced formula would be 2NO.
















Finally we went over balncing equations. He told us that the whole point is to make both sides equal for it to be balcnced. Also another thing was that the reaction is the product. Ex. 2Al+3Pb(NO3)2 -------> 2Al(NO3)3+3Pb. The numbers in red are what make it even.
Next Scriber: Ross