Thursday 3/24-Stacey-Unit 10 Chemistry Practice

Along with the chemistry review we had due today, it was also a food day (optional).
Remember, tomorrow is the last day of the quarter and our Thermochemistry test is tomorrow!
Below are the answers to the Unit 10 Chemistry Practice packet, we didn't have to do the first two pages of the packet (math skills and reading for information).

Our homework for tonight is to study for tomorrow's test. Also, make sure all the pages in your journal are finished!

Thursday 3/24 - Mike - Thermochemistry Review

Since it is the end of the third quarter, we started off class by eating all the food that everybody brought in for this quarter's food review today. After everybody was done eating, Mr. Tucker stamped our homework that was due today. Below you can see pictures of the homework, done step-by-step.

After stamping the homework, Mr. Tucker reviewed problems from all three pages with us in class. Following this review, we proceeded to discuss and take notes on energy diagrams. Below you can see a picture of the notes we took in class.

After taking notes there was only ten minutes left in class, so Mr. Tucker let us work on two review sheets on our own in class. Below you can see pictures of the review sheets, done step-by-step with work.

The homework for tonight is to STUDY FOR OUR TEST TOMORROW.

Thurs, 3/23, Eiesland

Today we started class by doing the Combustion Lab as a class. This lab's main question was: How much energy is released in the burning of candle wax? To figure this out, we measured and massed 100 ml of water in a beaker and then placed it over a small, burning candle underneath. Before we placed it above the burning candle, we massed the burning candle. We waited for the candle to heat up the beaker a little bit before taking the water's temperature again and then massing the candle one more time. Once we concurred that the mass went down because some of the wax had changed because of the reaction that took place (Wax + O2 -> CO2 + H2O + Heat), we were then able to plug our data into our formula (Heat = mc [delta] T).

Scroll up for the two pictures that explain all of our data and what we ended up doing for the equation.

After we finished the Combustion Lab, Mr. Tucker checked in our homework. We went through a few problems and if you want to see some problems and the answers, Kim posted some on her blog for Tuesday, March 22.

We learned something new today : Energy Diagrams! Mr. Tucker pointed out like 10 times that an Energy Diagram ( which has a curve) is NOT the same thing as a Heating Curve ( which looks more slanted steps ( 2 plateaus, 3 slopes). So don't confuse them! Here are the notes/diagrams from these two pages ( pages 7 & 8). ( scroll up for pictures)

Our homework for today is to do the Unit 10 Chemistry Practice packet ( but skip the math skills and reading for information sections) and if you want to, the 3rd quarter food review. It's due tomorrow ( Thursday) and I'm putting a picture on to show you what's required in the flyer. ( scroll up for pictures)

Tuesday 3-22-Bernstein-Energy Stoich

Here are the pictures from the last blog for questions 1 and 6 for pages 5 and 6 in your journals.

Use the pages from my last post for these answers.

The homework tonight is to finish page 5 and 6 in your journals. For question 1 part c, you do not have to answer that. The test is on FRIDAY so make sure you start studying and ask any questions you have referring to this unit!

Tuesday 3-22-Bernstein-Energy Stoich

1. The first thing we did today in class was get journal pages 5 and 6. The bottom picture is page5 and the top picture is page 6.

2. The next activity we did was go over the Heat Fusion Lab. If you were not hear within the last few days of class, you can get the pages from the previous blog. We first discussed what happened to the water and ice during this experiment. The ice was menting in the water. Two things happened in the cup:

1. Ice melted

2. The water was getting colder

In this experiment, we looked at what the endothermic and exothermic items were. The endothermic, or the process that gains heat, was the ice. As the ice was being stirred in the water, the ice was absorbing heat and making the ice colder. The exothermic, or process that losses heat, is the water because it is losing heat. Mr. Tucker drew us a picture of a glass with one ice cube in it. He then drew and arrow, coming from the water, to the ice cube. this shows the process that occurred in the experiment. The ice absorbed the heat coming from the water which caused the ice to melt and the water to lower in temperature. This picture also shows us how the ice is endothermic and the water is exothermic.

We also discussed the important notification that HEAT LOST = HEAT GAINED. The equation for this is M x C x delta T (Tf-Ti) = M x Hf (Heat of fusion).

3. The next thing we did was look at the data table from the experiment. We only did one trial for the experiment, so don't do trial 2. Our data that we got is as follows:

Trial 1

Mass of dry calorimeter: 4.02 g

Mass of calorimeter and water: 97.6 g (should be close to 100)

Initial Temp. of water: 23 degrees Celsius

Final Temp. of water: 4 degrees Celsius

Mass of calorimeter and water after ice melted: 121.23 g

4. We then began doing the Heat of Fusion Lab Calculations and Questions.

1. Find the mass of the original amount of water in the calorimeter. 97.60 g H2O(l)

2. Find the mass of the water resulting from the melted ice. 23.63 g H2O(s)

3. Find the change of temperature of the water. 19 degrees Celcius

4. Find the amount of heat lost by the original amount of water when it cooled. (specific heat of water is 4.18 J/g C)

97.60 g x 4.18J/ g C x 19 C = 7751.39 J sig figs! So the answer is 7751 J

5. Find Heat of Fusion for the ice. 7751 J= 23.63 g x Hf. Divide both sides by 23.63 g =328 J/G

6. Skip this problem

Questions.

1. Is the process of ice melting endothermic or exothermic? Heat goes into the ice cube, so endothermic

2. Is the process of ice freezing endothermic or exothermic? Since heat leaves the ice, making it freeze, it is exothermic

3. Compare your heat of fusion to that in your notes? Ours is 328 J/G and the real heat of fusion is 334 J/G.

5. After reviewing the lab, we began to do page 5 and our new lesson for the day, ENERGY STOICH. Above were the journal pages so look back to those for the problems. We did problems 1 and 6 together so that is what I am going to show you how to do.

Monday 3-21- Olivia- Thermochemistry

Today we started off class with picking up a lab and our homework. Mr Tucker than checked in the 10 minutes of homework we were to do last Thursday night. We then went through questions anyone had from the homework. It was page 2 and we went over number 4, 5, & 7.

To the left is the picture of the homework, but below is the picture of what we went over, step by step, in class.

After this, we did our first quiz of the unit, Heat Quiz. It was based on what we learned from last week before the chem day.

this quiz was 15 points and can be made up by Thursday.

The Unit Eleven test is on Friday March, 15th, so if you will be gone on that day for Spring Break, Mr. Tucker strongly suggests you take it before Spring break.

Finally, for the last five minutes of class, we went back to our lab tables and began the lab by heating the water that was initially 50 degrees Our homework for tonight is page 4 Heat Calculations 3 that we picked up in the beginning of class.

F-3/18- Audrey – Chemday

Today we went to the auditorium for chemday to watch an episode of MythBusters called Crimes and Myth-Demeanors 2.

The teachers handed out a paper with the questions related to the show.

Here are the following questions:

1. The fingerprint lock is an optical sensor.

2. What do Jamie and Andy have to do in order to break into Grant’s lock?

They need Grants fingerprint.

3. Which method of lifting prints works?

They added powder to the glue print.

4. Why doesn’t the paper print work?

It’s not three- dimensional.

5. In thermal motion alarms, what sets off the alarm?

Infrared energy

6. Why did Tory set off the alarm?

His body heat was picked up by the alarm.

7. What problems are involved with using a CO₂ extinguisher to cool Tory?

It would be difficult to have a consistent temperature in the body because it’s just going to be a blast. So he can just heat it right back up in the middle of the room. Also it is dangerous can it can cause frostbite.

8. Which material was more like human skin? Did it work?

They use a Ballistics gel. But no it didn’t work because the ridges are not deep enough.

9. Was the Team able to covertly get Grant’s fingerprint?

Yes, Carrie is able to get Grant’s fingerprint by using a cd case.

10. Why does the second print work?

The lines of the fingerprints are clearer.

11. Why did the neoprene suit set off the alarm?

The longer Tory wears the suit the heat from his body is transferred in the suit.

12. Did the Predators method of pasting yourself with mud fool the alarm?

No, because the body heat warmed up the mud. Also there are mud tracks left.

13. How did Adam’s fingerprint work?

They made a latex copy that is planted on his heated thumb and then he licked it.

14. What happened with the photocopy print?

They are able to get in.

15. What happened when they increased the room temperature?

A huge hot stream is flowing in the room setting off the alarm.

16. Did a near naked Grant fool the alarm?

No, because the alarm is just too sensitive.

17. How does the big pane of glass work?

The glass can block the infrared of the body.

18. Did the glass method work?

Yes

19. What is glass- re- locker?

A pane of breakable glass within the safe itself that if broken activates locks that makes the door impenetrable.

20. How many milliliters of nitroglycerine does Adam think he needs?

140 ml of nitroglycerine

21. Where are they testing the safe?

They are doing their test at a sewage plant.

22. How big is the glass in the actual safe?

The size is a small glass in the middle of the safe.

23. What are the five steps to blow up the safe?

Step 1, is to bore a hole in the top of the safe with a thermo lance. Step 2, is to fill the safe with water. Step 3 is to lower explosives into the safe. Step 4 is to blow the door of the safe and step 5 is to get the money and run.

24. What was the problem when they burned a hole in the safe?

It also burned everything in the safe.

25. How does the ultrasonic motion detection work?

It sets out a very high frequency sound wave which bounces off in all the wall of the room and comes back to the sensor to create a pattern.

26. What material soaks up the sound?

A thick rug.

27. Does Carrie’s bird suit work?

No it didn’t.

28. Does the bed sheet work? Why?

Yes, because the bed sheet is actually absorbing the sound wave.

29. What was the last method used to fool the alarm? Why does it work?

The last method is to slowly walk in the room. This method worked because the sensor has a threshold level of movement that needs to trigger it.

30. Were Adam and Jamie even able to copy the safe breaking Crime?

Yes

REMEMBER THE HW ON THERMOCHEMISTRY WHICH WE WILL GO OVER ON MONDAY.

3/17/2011 Thursday

Today we started class by picking 2 sheets(thermochemistry/ Energy notes) and we got a worksheet at the end of the class. when you do your worksheet you are supposed to time yourself in 10. You get your hands off of your worksheet when 10 minutes is over. Mr. Tucker stamped the homework which was the post-lap.

- Temperature : Average kinetic energy of the particles in a substance(oC,oF,K). oF is out because we are not going to use it.

-Heat is transfer of energy(Joules)


Endothermic:something gains heat

Exothermic - something loses heat.

-For oC, H2O is always 4.18


- Then, we went over couple of problems which is about THermochemistry.








- This is the homework.

W-3/16/11-Thermochemistry

-Today we started class by picking up three sheets from the front. The first sheet was called, Heating Curve of Water Lab and this was the prelab questions, the second sheet had the procedure for the lab, and the third sheet was graph paper.

- Before we did anything Mr. Tucker talked to the class about the schedule for this unit (it is up on moodle!). We have a chem day this friday. Next thursday we will have the quarter three food day, Mr. Tucker will talk more about that. Also, thursday next week we are reviewing for the test ( WHICH IS ON FRIDAY!).

- After we discussed the scheduale for this unit, Mr. Tucker gave us some time to look through the prelab questions that we picked up in the begining of class, and told us to think about the questions and answer all six of them.

This is what the prelab questions look like (the whole sheet has 6 questions)

- After we answerd the questions on our own, we went through the questions as a class.

- Afterwards, Mr. Tucker told us that we are going to be doing a lab today and he explained the procedure.

- We had to fill a 400 ml beacker with 200 ml of water and place 10 icecubes into it.

-Then we stired the icecubes in the water for one minute and recorded the temperture of the water

- Next, we placed the water on a hotplate that was turned onto 10, and heated the water.

It was important not to touch the hotplate or the thermometer.

-We had to keep stirring the water and recording the temperture of the water every minute, untill the water started to boil.

- While we were doing this we had to record the data and observations on the second sheet we picked up at the begining of class.

This what that sheet looked like (on the bottom of the sheet we had to write the conclusion, which are two postlab questions).

Finally, with the time remaining at the end of class, we had to make a graph from the data we collected from this lab. We used the graph paper we picked up in the begining of class, to make this graph.

This is what the graph paper looks like

Homework: Finish the graph

Finish the 2 Postlab Questions

Fri, Kin./EQ Review / Tucker

Sorry for the lat post, internet issues.  GOOD LUCK STUDYING, SEE YOU ON MONDAY!!

Kinetics & Equilibrium Review Answers

1.       Particles COLLIDE in the correct orientation and with enough force

2.       As temperature increases particles move faster and collide more often and with more force

3.      Surface area, concentration, and catalysts

4.      Surface area is increased

5.      Decrease temperature, decrease concentration of reactants, decrease surface area…..all would lead to fewer COLLISIONS

6.      The reactions continue at equilibrium….they are just at the same rate.

7.      K=  [H2O]² / [HCl]⁴…….others are not used b/c liquid and solid

8.      0.09M

9.      If O2 is removed the reaction shifts to the LEFT (to add more O2)
if reaction shifts left, then NO2 and O2 increase and NO3 decreases on the graph

10. 

a)       Opposite of remove H2O is ADD H2O so shift left

b)        For this problem, write the word HEAT on the reactant side (left).
  the opposite of decrease temp in INCREASE TEMP so shift left towards the heat

c)      No Shift, SiCl4 is a liquid

d)      Opposite of Remove HCl is ADD HCl, so shift right

e)      When the word pressure is mentioned count the moles of gas on each side of the equation…..2moles gas on left, 4 moles of gas on the right…..Opposite of increase pressure is decrease pressure so go towards the side with fewer moles of gas…..shift left

11.   Increase temp, shift left

Add more S, No shift
Decrease H2-  shift left
Add a catalyst……  skip, do not worry
Increase volume…..skip, do not worry

12.   K = [H2S] / [H2]

13. 
a)  True, if K is greater than 1 the products are favored  (K = P/R)

b)  False, if K is less than 1, the reactants are favored

c)  Temp does not affect K, just concentrations of P and R

14.   

a)  N2(g) + 2H2(g)  à  2NH3(g)

b)  O2(g) + C(s)  à  CO2(g)…….this question is trick, but the C must come from    somewhere and the reason it is excluded from the K equation is b/c it is a solid

15.  First, find the concentrations of all substances by dividing mols by 5L

            [NH3] = 0.40M,  [H2] = 0.60M,  [N2] = 0.20M

        Then, figure out the K equation……K = [NH3] / [N2] x [H2]³

            K=  3.7

Thu, Kin./EQ Practice / Tucker

Chemistry Practice ANSWERS:

Math Skills:
From top left to right
1.  2.22
2.  125
3.  8
4.  1.17E-5
5.  1.33
6.  0.942
7.  10
8.  0.868
9.  7.13E-5

Reading for Information:
a)  about 98.6F, Homeostasis…like hair and shivering
b)  about 98.6F, Homeostasis, like sweating
c)  Yes, body keeps changing in response to external conditions
d)  House heats up, thermostat increases, air conditioner turns on, House cools down, Thermostat decreases, air conditioner turns off
e)  Body changes OPPOSITELY in response to stresses(changes) on it…it tries to fix itself.

Data Interpretation:
a)  Temp, Time
b)  Amounts of A and B
c)  about 1-2seconds
d)  Inverse, as T goes up, time goes down
e)  Cannot predict, A may not react with C

Unit 11 Problems Broken Down:
1.
a.  K=  [P] / [R]
b.  K = [NO2]² x [Br₂] / [NOBr]²c)  NOBr-  109.9g/mol,  NO- 30g/mol, Br2-  159.9g/mol
d)  NOBr-  0.910 mol,  NO- 0.333 mol, Br2- 0.625 mol
e)  5L
f)  mol / L
g)  NOBr-  0.182M,  NO- 0.0667M, Br2-  0.0125M
h)  K=  0.00168

2.
a)  double arrow
b)  forward reaction = reverse reaction, concentrations of reactants and products are constant
c)  +, reactant side…….do not worry, I will always tell you what side the heat is on for now
d)  2mols reactant, 3 mols product
e)  More,  Less
f)  GIVEN
g)  add SO2, right, SO2 and O2, SO3, more moles gas, increase
h)  decrease O2, left, SO3, SO2 and O2, less moles gas, decrease
i)  decrease temp, right, SO2 and O2, SO3, more moles gas, increase
j)  increase pressure, right, SO2 and O2, SO3, more moles gas, increase

W 3/9 - Melanie - Equilibrium

First thing we did was pick up 4 journal sheets. They were all a part of one lab, Le Chatelier's Principle and Equilibrium. It included the pre-lab, data, and post-lab sheets.

Mr. Tucker will not be in class on Thurs, March 10 and Fri, March 11. WE WILL STILL HAVE THE UNIT 11 TEST ON MON, MARCH 14.

Mr. Tucker stamped journal pages 4 (Le Chatelier 1) & 12 (Equilibrium 2) for completion. We then went over the answers

don't forget:

PRESSURE=MOL/GAS

on journal page 4, remember when something is increased or decreased, you do the opposite.

EX: 2a) oxygen gas is removed (THAT MEANS IT NEEDS TO BE ADDED) therefore you go to the right.

K=[P]/[R] (product/reactant)

[concentration is in brackets]

Then after we completed the Le Chatelier's Principle and Equilibrium Lab together as a class. We read the pre-lab together and Mr. Tucker dropped the different substances into the CoCl2 and we wrote down the observations that we had, the color changes that occurred.

We then answered some of the post-lab questions as a class as well.

At the end of the period Mr. Tucker passed out the Unit 11 Study Guide.

HOMEWORK: Start studying, if you have trouble with any of the concepts go to the TLC for help.

Chemistry Period 2nd - Equilibrium - Nikki Lipinski (March 8, 2011)

Today, we started Chemistry by taking four jurnal sheetes. The sheetes included:

- Frayer Charts

- Equilibrium notes

- Jurnal Sheet nr. 4 - Le Chatelier 1

- Jurnal Sheet nr. 12 - Equilibrium 2

Mr. Tucker has begin class with reminding us that he will not be in school on Thursday March 10 and Friday March 11, so we have two days for review for TEST on Monday March 14, 2011.

Next we and Mr.Tucker read pages from our textbook (549 - 550), Chapter 18 Section 2. The text was about Reversible Reactions and Eequilibrium. Now we know that a reversible reaction is one in which the conversion of reactants to products and the conversion of products to reactants occur simultaneously.

Example:

2SO_{2 (g)} + O_{2 (g) <------>} 2SO_{3 (g)}

After reading Mr. Tucker gave us few minutes to fill up Frayer charts. We were suposed to write our definition, picture, non- examples and examples of EQ (equlibrium). Then our chemistry teacher explained to the class what is equlibrium.

Equlibrium is a revesible reaction in whichconcentration of reactants + products are constant. Equilibrium is only for gases (g) and substances which soluble in water (aq).

The Equilibrium can be measured:

Keq = [products] / [reactants] [] - stands for M

Homework:

Jurnal page 4 and questions 1,2 and 4 from page 12

Ellie-Tuesday, 3/7

Today in class we...

1) Picked up 4 journal pages and a short reading

~The four journal pages were "Frayer Charts", "Equilibrium Notes", "Equilibrium 2"(page 12), and "Le Chatelier 1"(page 4)

~The reading was on equilibrium

2) Read through the short reading. Used the reading to fill in The Definition, Picture, Non-example, and Example on the "Frayer Charts" journal page.

3) Went over Frayer Charts and had people come up to the projector and show their examples/pictures.

4) Went through the Equilibrium Notes, and went through how to solve if you shift to left (reverse) or right (forward)

~A(g)+B(G)<---->AB(g)+heat

More/Less Products:

Add more AB, shift left

Take away AB, shift right

More/Less Reactants:

Add more B, shift right

Take away A, shift left

Energy:

Lower the temp., shift right

Increase the temp., shift left

Pressure:

Increases pressure, shift right

Decreases pressure, shift left

5) Moved on to Number one on the journal page "Equilibrium 2"

1. 2 NH3(g) <----> N2(g)+3H2(g) K=6.56 x 10^-3

In an equilibrium mixture of the gases above [N2]=0.045M and [H2]=0.0056M. Find [NH3].

K=[N2] x [H2]^3

---------------

[NH3]^2

6.56 x 10^-3

.00656= .045M x (.0056)^3

------------------------

X^2

.00656= .045 x .000000176

------------------------

X^2

X^2 x .00656 .000000008

----------------- = ------------------

.00656 .00656

Square root of x^2=square root of .00000125

X=.001118

6)Did number one on Le Chatelier 1

a. carbon dioxide is removed- right

b. water vapor is added-right

c. the pressure is increased-NS

7) Was assigned homework: to do numbers 2 and 4 on Equilibrium 2 and numbers 2 and 3 on Le Chatelier 1

Thu, 3/3, Tucker

Today each lab group performed a short lab involving a reaction with alka-seltzer and water.  The reaction produced a gas and when this reaction occured in a flask with a balloon placed over the top of the flask, we were able to time the reaction...how long did it take for the balloon to inflate?  Since different groups investigated different independent variables, we then shared data/conclusions with the class.  The three labs are outlined below:

WE JUST WROTE THIS LAB IN OUR JOURNALS!!

Lab 1:
Procedure:  Place 1/4 alka seltzer tablets in 25ml of water in a 50ml flask and place a balloon over the top of the flask.  Time how long it takes for the balloon to inflate.  Repeat with 1/2 and full tablets.
Data:
1/4tablet-  45sec
1/2 tablet-  14sec
1 tablet-  6sec
Conclusion:  As concentration increases, so does the speed of the reaction

Lab 2:
Preocedure:  Place 1/2 alka seltzer in in 25ml of water in a 50ml flask and place a balloon over the top of the flask.  Time how long it takes for the balloon to inflate.  Repeat with a crushed alka-seltzer (which has more surface area!)
Data:
1/2 tablet -  16sec
1/2 tablet crushed- 5sec
Conclusion:  As surface area increases, so does the speed of the reaction

Lab 3:
Procedure:  Place 1/2 tablet of alka-seltzer in 25ml of room temperature water (22 degreesC) in a 50ml flask and place a balloon over the top of the flask.  Time how long it takes for the balloon to inflate.  Repeat this with 5degreesC water and 50 degreesC water.
Data:
5C- 2min, 20sec
22C-  20sec
50C-  4sec
Conclusion:  As temperature increases, so does the speed of the reaction

The independent variables for the lab were concentration, surface area, and temperature
The dependent varibale for the lab was time / speed of the reaction
The controlled varibales for the lab were the size of flask, type of tablets, and amount of water.