Tuesday, September 29, 2015
9/28 Biology update and homework due 10/5
Hi folks,
Today we took a quick look at a number of topics related to chemistry and biology. We looked at acids and bases, buffers, salts, and dynamic equilibrium. We also looked at solubility and concentration and conducted a quick lab to find the solubility of salt and sugar in 100g of water.
Homework due 10/5
Read pages 35 - 44 in the text book
Do questions #'s 10 - 19 on page 46
I'd also like you to do a lab report based on the lab report template I've included in this email.
The template should be rather self explanatory but here are some specifics to help you out.
1. For the hypothesis, state whether you originally felt that more salt or more sugar would dissolve in the solvent.
2. The data table will be rather short with just the grams of sugar and grams of salt that dissolved.
3. The graph should be a bar graph with the mass of salt and the mass of sugar that dissolved.
4. For your conclusion, I'd like you to state which substance was more soluble and whether or not that matched your hypothesis. I'd also like you to do an percentage error calculation. Percentage error is calculated by comparing your findings to known findings. The formula is (your results - actual results/actual results) x 100. You are hoping for a 0% error. Don't worry about whether the answer is positive or negative. The solubility of salt is 35.7 g/100 mL water at 20°C. Sugar is 206g/ml water at 20°C. If you find a large percentage error, try to give some explanation as to why your results were off.
Today we took a quick look at a number of topics related to chemistry and biology. We looked at acids and bases, buffers, salts, and dynamic equilibrium. We also looked at solubility and concentration and conducted a quick lab to find the solubility of salt and sugar in 100g of water.
Homework due 10/5
Read pages 35 - 44 in the text book
Do questions #'s 10 - 19 on page 46
I'd also like you to do a lab report based on the lab report template I've included in this email.
The template should be rather self explanatory but here are some specifics to help you out.
1. For the hypothesis, state whether you originally felt that more salt or more sugar would dissolve in the solvent.
2. The data table will be rather short with just the grams of sugar and grams of salt that dissolved.
3. The graph should be a bar graph with the mass of salt and the mass of sugar that dissolved.
4. For your conclusion, I'd like you to state which substance was more soluble and whether or not that matched your hypothesis. I'd also like you to do an percentage error calculation. Percentage error is calculated by comparing your findings to known findings. The formula is (your results - actual results/actual results) x 100. You are hoping for a 0% error. Don't worry about whether the answer is positive or negative. The solubility of salt is 35.7 g/100 mL water at 20°C. Sugar is 206g/ml water at 20°C. If you find a large percentage error, try to give some explanation as to why your results were off.
Wednesday, September 23, 2015
Great video on study habits
Hi guys,
I though you may find this video useful. It has some great "scientific" tips for how to study better. I wish I would have known this stuff in high school!
Never Stop Wondering,
Science Jim
Tuesday, September 22, 2015
9/21 Biology update and homework due 9/28
Hi folks,
Today we did a whirlwind tour of basic chemistry in order to get everyone ready for the upcoming "Basic Molecules of Biology" block of class. Here's the link to my favorite (yes, I'm geeky enough to have a favorite) periodic table website.
Homework:
Read the book pgs. 31- 34
Do Section I Review on pg. 34 #'s 1-6 and 8.
Answer the following questions:
(I've included the answers below so that you can check your work. Be sure you understand these, quizzes are coming.)
1. Draw the probable number of bonds for the following elements:
a. O b. C c. I d. Tl e. Al f. Mg
2. Draw the following molecules (use as many atoms as you need to make the bonds)
a. Li & Br
b. Mg & Te
c. K & P
d. O & O
e. N & N
f. C & O
g. C & H
h. C & O & H
Answers (no peeking until your done!)
1. Hard to draw with email so I'll just give #. a. 2 b. 4 c. 1 d. 3. e. 3 f. 2
2. a. Li-Br
b. Mg=Te
c. P with 3 K's around it
d. O=O
e. N triple bond N
f. O=C=O
g. Many ways but the simplest is C with 4 H's around it
h. Many ways but one is C=O and put 2 more H's around the C
Tuesday, September 15, 2015
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