Today, we started class by getting our chemistry lab notebooks from the lab tables in the back of the room. Mr. H then went around the room and gave everyone their rubrics for the labs that we did in our notebook. Mr. H then went on to talk about how if you had a bad test grade, then you should go and see him. He mentioned that he won't be available tomorrow, but that any other day he would be available.
Mr. H then officially began class by introducing to the class another 50 point web assign that will be due in about 3 weeks. If you want to know more about it, here is the link:
http://gbschemphys.com/honchem/index.html
Mr. H did tell us though that in order to get 100% on this web assign, you have to get at least 35/50 questions correct. As an addition to this web assign, Mr. H reminded the class that just like the previous unit, there will be frequent quizzes throughout this unit and a test that will be in three weeks.
Mr. H then began his lesson of the day, which was an introduction to Acids & Bases, by letting us know that there will be a lab tomorrow in class, so be sure to bring your lab notebooks. He then proceeded to write important notes on the board which are essential in understanding Acids and Bases. The Notes are as followed:
Acids and Bases
Definitions:
1) observable properties (Lab AB1)
2) Arrhenius (Early 1800s)
Conductor: it needs to have ions in order to be considered a conductor
^^One of the examples that Mr. H gave about conductors was the light bulb with the two rods. He tested to see if multiple liquids were conductors by putting each liquid in a beaker and then placing the beaker in the two rods. If the light bulb lit up, then we knew that that liquid was a conductor. If it didn't, then we knew it wasn't. The liquids that Mr. H experimented with were HNO3, HCl, HC2H3O2. The first two liquids lit the light bulb really bright, so we were able to conclude that those liquids had lots of ions in them. When we experimented with HC2H3O2, (a.k.a. vinegar), we noticed that the light bulb turned on, but the light was very dim. From this, we were able to conclude that vinegar is a weak acid on the pH scale, and therefore is a weak conductor.
Acids: H___ ---> H+ + ____-
A= anions
Bases= ____OH----> _____ + OH-
^^ Mr. H continued to use the light bulb as a conductor tester, but this time, he used KOH and NaOH, which are solids, and mixed them in a beaker of water. He once again did the same process as before, and after experimenting with both, the class saw how the light bulb became very bright when both of the solutions were tested on the light bulb prongs. This shows that KOH and NaOH are two very strong bases and have plenty of ions in the solid to become a conductor.
Strong Acids: HNO3------------> H+ + NO3- (High K) <--------- lot of reactant, little product
<---
Weak Acids: HC2H3O2<------------ H+ + C2H3O2- (Low K) <------- lot of product, little reactant
--->
Strong Acids to know:
1)HCl
2) HBR
3) HI
4) HNO3
5) H2SO4
6) HClO4
Strong Bases to know:
1) LiOH
2) NaOH
3) KOH
4) Ca(OH)2
5) Sr(OH)2
6) Ba(OH)2
After writing these notes and copying them, Mr. H had the class open up their unit 12 chemistry packets to page 1 and had us work on problem 1. Before doing problem 1, it was essential to know that:
an acid= a substance which produces hydrogen ions when it dissolves in water
a base= a substance which produces hydroxide ions when it dissolves in water
Knowing this, the class was able to answer question 1. The answers are as followed:
A B B
N B N
B A N
The class then went on to do problems 2, 4, and 5. (#3 was a review)
#2
a) H+ + NO3- (Acid)
b)Na + + OH- (base)
c) H+ + CN- (acid)
d) Ca2+ 2OH- (base)
#4 ( these answers correspond to a table, so the name goes on the left part of the table and the formula goes on the right part)
hydrochloric acid
HBr
hydroiodic acid
nitric acid
H2SO4
ClO4
lithium hydroxide
sodium hydroxide
KOH
calcium hydroxide
Sr(OH)2
BA(OH)2
#5
a) [H+] = 6.0M
b) [OH-]= 3.0 M
c) [H+]= 1.0 M
d) [OH-]= 2.0M <------ this is because the product is double the reactant
This concluded our lesson for the day. Tonight's homework: 13.2-3 Rdg Sheet.
The Daily Joke: What do you do with dead chemists?
Answer: Barium
