Thursday, January 31

Sections 8, 9 & 11: At the beginning of class today, I asked you to reflect on your % error. Tonight, I want you to write a short paragraph covering these questions:

• Why do you think your % error from procedure 1 was high or low?
• What steps could you have/did you take when finishing procedure 2 to have a lower % error calculation?
• How does stoichiometry help us understand % error? Why is % error important?
• Look up, or postulate, a situation in the lab where high % error could be detrimental.

Wednesday, January 30

All Sections:
1) Use the sample data given to you to answer post-lab questions 1-3 (trial 1 AND trial 2)
2) Use your own data to answer the same questions (one trial ONLY) on the back of your lab manual.

Here's the equation for percent error:



(Reminder - the 'theoretical' value is the molar mass calculated from the periodic table)

Tuesday, January 29

Section 8: Work on your pre-lab (in pencil!)

Monday, January 28

Section 8 (JUNIORS): For next Monday, read these two links that relate to today's video:
http://map.gsfc.nasa.gov/news/
http://science.howstuffworks.com/dictionary/astronomy-terms/dark-matter-dark-energy.htm

Come in with a short paragraph summarizing what you've learned. Feel free to use more sources if you don't find these sufficient for understanding the material. 

Section 10: Do these!:

1. Write the balanced equation for the combustion of ethyl alcohol,

C2H5OH. If 3.662 moles of ethyl alcohol are burned, how many moles of water can be formed?

2. In the reaction P4 + 5 O2 ® 2 P2O5, how many moles of oxygen are consumed each time 0.500 mol of P2O5 is formed?

3. In the reaction in question 2 above, how many grams of diphosphorus pentoxide could be formed from 0.34 moles of oxygen?

4. How many grams of ammonia (NH₃) will be produced when 25.0 g of CaCN₂ react with excess water in the reaction below? 

CaCN₂ + 3 H₂O ® CaCO₃ + 2 NH₃

Friday, January 25

Sections 9 & 11: Do these!:

1. Write the balanced equation for the combustion of ethyl alcohol,

C2H5OH. If 3.662 moles of ethyl alcohol are burned, how many moles of water can be formed?

2. In the reaction P4 + 5 O2 ® 2 P2O5, how many moles of oxygen are consumed each time 0.500 mol of P2O5 is formed?

3. In the reaction in question 2 above, how many grams of diphosphorus pentoxide could be formed from 0.34 moles of oxygen?

4. How many grams of ammonia (NH₃) will be produced when 25.0 g of CaCN₂ react with excess water in the reaction below? 

CaCN₂ + 3 H₂O ® CaCO₃ + 2 NH₃

Thursday, January 24

Section 8: Complete #3-5 (all parts) on your stoichiometry worksheet.

Sections 9 &11: Complete #5 on your stoichiometry worksheet. Also, complete the pre-lab questions in your lab (page 2). You MUST read pg.1-2 carefully in order to complete this task.
Do your work in pencil!

Section 10: Complete the assignment posted for sections 8 & 11 yesterday.

Wednesday, January 23

Section 9: On the worksheet we started in class today, complete problems 1-4 (all parts). Also, look over procedure 2 in your lab, so that you are ready to go for tomorrow.

Sections 8 & 11:  At the bottom of this post, you will find the answer to #1 on your worksheet.

For homework, complete #2, as well as, the problems below:

1)For the balanced equation shown below, how many moles of S₂Cl₂ be produced by 0.8178 moles of CS₂?
CS₂+3Cl₂=>CCl₄+S₂Cl₂

2) For the balanced equation shown below, how many moles of C₂H₆S will react with 0.02166 moles of SO₃?
C₂H₆S+5O₂=>2CO₂+3H₂O+SO₃

3) For the balanced equation shown below, how many moles of KOH will react with 0.8931 moles of K₂O?
K₂O+H₂O=>2KOH

4) For the balanced equation shown below, how many moles of Cl₂ will react with 0.4030 moles of H₂O?
4C₂H₅Cl+13O₂=>8CO₂+10H₂O+

Midterm

Midterm review packet answer key can be found at the bottom of the webpage.

Don't forget, I will be available to answer questions on Tuesday after exams (room 3K2).

Midterm is Wednesday at 9am!

Good luck!!!

Thursday, January 10

Section 8: At the bottom of the website, you'll find the powerpoint from today's class. The slides we looked at today start at number 38.

In your green packet complete:

• #1 & 3 on the 'Percent Composition and Molecular Formula Worksheet' (front page)
• 'Empirical and Molecular Formula' wksht #1,2,3 (back page of the wksht listed above) and #1-5 (last page)

**Recommended review packet problems are all %comp and empirical formula problems

Section 10: Study for tomorrow's quiz!

**Recommended review packet problems are all %comp, empirical formula and molecular formula problems 

Wednesday, January 9

Section 10: At the bottom of the website, you'll find the powerpoint from today's class. The slides we looked at today start at number 37.

In your green packet:

• Complete the back page of the 'Chapter 7 Worksheet'
• Complete #1 & 3 on the 'Percent Composition and Molecular Formula Worksheet'

Wednesday, January 9

Section 10: At the bottom of the website, you'll find the powerpoint from today's class. The slides we looked at today start at number 37.

In your green packet:

• Complete the back page of the 'Chapter 7 Worksheet'
• Complete #1 & 3 on the 'Percent Composition and Molecular Formula Worksheet'

Tuesday, January 8

Section 8: For each of the following, calculate the number of grams of these elements.
1) Silicon in 20.0 g SiO₂

2) Calcium in 4.5 g CaCO₃
3)  Hydrogen in 115 g H₃PO_4
4) Magnesium in Mg₃(PO₄)₂

**Recommended review problems - all electron configuration problems

Section 9: 

• Finish your Chapter 7 Worksheet.
• % comp and molecular formula wksht #1,3 
• empirical and molecular formula wksht #1,2,3 (front side) and #1-5 (back side)

**Recommended review packet problems - 37-40

Section 10: Complete page 1 of the green packet (front and back) and #1 on the next page (Chapter 7 Worksheet). You will be having a quiz on Thursday on what we learn this week.

Hydroxide: OH^-                  Permanganate:  MnO₄^-

Bicarbonate: HCO₃^-           Ammonium: NH₄⁺

Carbonate: CO₃^2-               Acetate: C₂H₃O₂^-

Sulfate: SO₄^2-                    Hydrogen Phosphate:    HPO₄^2-

Sulfite: SO₃^2-                    Dichromate: Cr₂O₇^2-

Phosphate: PO₄^3-                

Nitrate:  NO₃^-

Nitrite: NO₂^-

Chlorate: ClO₃^-

Cyanide: CN^-

**Recommended review packet problems for tonight 25-35.

Section 11: In your green packet, complete % comp and molecular formula wksht - front and back.

**Recommended review packet problems - 37-40

Monday, January 7

Section 8:  Complete page 1 of the green packet (front and back) and #1 on the yellow sheet (Chapter 7 Worksheet). You will be having a quiz on Thursday on what we learn this week.

Section 9: Complete page 1 of the green packet (front and back) and the front of the Chapter 7 Worksheet. You will be having a quiz on Wednesday on what we learn this week.

Section 11: Complete page 1 of the green packet (front and back) and #1 on the Chapter 7 Worksheet. You will be having a quiz on Wednesday on what we learn this week.

Hydroxide: OH^-                  Permanganate:  MnO₄^-

Bicarbonate: HCO₃^-           Ammonium: NH₄⁺

Carbonate: CO₃^2-               Acetate: C₂H₃O₂^-

Sulfate: SO₄^2-                    Hydrogen Phosphate:    HPO₄^2-

Sulfite: SO₃^2-                    Dichromate: Cr₂O₇^2-

Phosphate: PO₄^3-                

Nitrate:  NO₃^-

Nitrite: NO₂^-

Chlorate: ClO₃^-

Cyanide: CN^-

All: Recommended review packet problems for tonight 25-35.

**You may to quiz corrections on your chapter 6 quiz!! Due on Wednesday.

Friday, January 4

Complete #1-5 in your midterm review packet

Thursday, January 3

Section 8: Finish your pink worksheet from class today. Also, complete problems #14, 15 & 16 on page 290 of your textbook.

Sections 9-11: Finish your pink worksheet from class today.