Hi folks,
Today we got into the concept of exothermic and endothermic reactions. Exothermic reactions are ones that release heat. Endothermic reactions are reactions that absorb heat. To see these reactions, we took several different substances and mixed them together to see if the temperature went up or down.
Homework due 4/4 is to:
Read the text book pages 288 - 293
Do Review Questions #'s 29 - 33 on page 302
Do Exercises #'s 28-30 on page 304
Do Problems #'s 5-7 on page 305
Saturday, March 29, 2014
Sunday, March 23, 2014
Chemistry Update 3/21
Today we had an amazing fun lecture (irony) on oxidation-reduction reactions. This is a fairly tricky concept because there are so many things going on with these equations and the vocabulary is counter-intuitive.
Homework due 3/28
Read pgs. 337 - 357
Answer Review Questions #'s 1-5
Answer Exercises # 1 - 6
Also, do the 4 problems on the enclosed .pdf. Answers are enclosed as well but please…no peeking until you're done.
Friday, March 21, 2014
Recording of 3/21 class
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Chem 2013 week 24
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Sunday, March 16, 2014
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3/14 Chemistry Update and Homework Due 3/21
Hi folks,
This week we talked a bit about percentage yield, theoretical yield, actual yield, and what needs to be present in order to have molecules react with one another.
Homework for 3/21 is to:
Read 271 - 288 in the Conceptual Physics book
Do Review Questions #'s 17 - 28
Also, do the 2 questions on the enclosed .pdf.
This week we talked a bit about percentage yield, theoretical yield, actual yield, and what needs to be present in order to have molecules react with one another.
Homework for 3/21 is to:
Read 271 - 288 in the Conceptual Physics book
Do Review Questions #'s 17 - 28
Also, do the 2 questions on the enclosed .pdf.
Saturday, March 8, 2014
Chemistry Class for 3/7
Hi folks,
Yesterday's chemistry class was a bit of a mess and I want to explain what happened there.
I lost power early Friday morning but assumed it would come back on quickly. Then I went to teach Friday Enrichment at 11 (which somehow had power) and got home around 12:30. At that point, I still didn't have power and neither did the clubhouse. However, it was too late to contact folks, especially since I did not have email. So, I showed up at the clubhouse with extra coats and blankets ready to hold class if folks could make it. At 1:40 only 3 folks had arrived so I cancelled class.
Sorry for any confusion and inconvenience that was caused yesterday. Let's hope that's the last of this weather nonsense!
Science Jim
Yesterday's chemistry class was a bit of a mess and I want to explain what happened there.
I lost power early Friday morning but assumed it would come back on quickly. Then I went to teach Friday Enrichment at 11 (which somehow had power) and got home around 12:30. At that point, I still didn't have power and neither did the clubhouse. However, it was too late to contact folks, especially since I did not have email. So, I showed up at the clubhouse with extra coats and blankets ready to hold class if folks could make it. At 1:40 only 3 folks had arrived so I cancelled class.
Sorry for any confusion and inconvenience that was caused yesterday. Let's hope that's the last of this weather nonsense!
Science Jim
Saturday, March 1, 2014
2/28 Chemistry Update and Homework due 3/7
Hi Folks,
Today we did a lab were we used the reaction of baking soda and vinegar to inflate a balloon. We changed the amount of baking soda that we used while we kept the amount of vinegar the same. This allowed us to get a little more in touch with the concept of limiting reagents
.
After looking at the quiz, it appears that some folks could use a bit more practice with limiting reagents. So here are 4 questions to help you out with that need. :) I've included a .pdf of the answers as well. These will be due next week.
For many of you, I also HIGHLY recommend going back and taking a look at naming ionic and covalent molecules. Lots of you guys are still struggling with that. Best way to do that is to grab some of those old quizzes and test yourself. Your final grade will thank you.
1.You combine 10.0 grams of hydrogen gas and 15.0 grams of oxygen gas. How many grams of water vapor are made? Which is the limiting reactant?
2H2 +O2 --> 2H2O
2. If 5.00 grams of copper metal react with a solution containing 20.0 grams of AgNO3, which reactant is limiting and what mass silver is produced?
2AgNO3 + Cu -->2Ag + Cu(NO3)2
3. 20.0 grams of potassium hydroxide react with 15.0 grams of ammonium sulfate calculate the grams of potassium sulfate produced.
2KOH + (NH4)2SO4 --> K2SO4 + 2NH4OH
4. In the reaction of chlorine and sodium to form sodium chloride, determine (1) the mass of sodium chloride produced and (b) the amount of excess reactant left if 30.0 grams of chlorine react with 30.0 grams of sodium
2Na + Cl2--> NaCl
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