CambridgeChem

Extra Credit Assignments

2006-12-09T18:10:00.000-06:00

The available assignments are by initials. Get to work on these if you want the credit.

TB - Jan Baptista Van Helmont
NC - Johann Joachim Becher
NG - Robert Boyle
BH - Joseph Black
DH - Georg Ernest Stahl
BJ - George Brandt
JK - Axel Fredric Cronstedt
EL - Johann Gottlieb
OM - Peter Jacob Hjelm
EP - Daniel Rutherford
MS - Jacob Berzelius
ES - Karl Wilhelm Scheele
PS - Stephen Hales
VS - Democritus

Except for the obvious exception, these are men who did their work in the 18th and 19th centuries. Remember, three sources, at least on from a real physical book with actual pages, so go to a library. Use internal citations so I know where your info is coming from. These are research papers, not cut-and-paste jobs, so I expect quality academic work.

Tommorrows Quiz

2006-10-16T21:20:00.000-05:00

You are only responsible for what appears in the text. If you have studied, you will not find any odf the material beyond you!

Chapter 2 quiz Monday!!!!!!

2006-09-09T13:28:00.000-05:00

Here are some solved problems for the end of chapter 2.

2.99 You are going to need two pieces of information, the volume and mass of the pumpkin. The mass is easy, you simply use a scale. Let's imagine that we find the pumpkin weighs 2.50 kg. Next you need to figure out a weigh to find the volume of this irregularly shaped object. I would recommend immersion in water. Let's say we fing the pumpkin displaces 5.0 L of water. Since density is usually expressed in terms of g/mL, we need to convert. 2,500 g divided by 5000 mL gives us 5.0 * 10^-1 g/mL.

It is interesting to note, this means the pumpkin will float so you would have devised a way to secure the pampkin underwater for the displacement measurement.

2.101 This is a good one. If you have a container of mercury handy (who doesn't) dropping the two pieces of metal in will distinguish them by their density. The lead will float, the gold will sink. I know it's strange to think of lead floating, but that is the nature of lead. Also, if you have ever had the opportunity to hold a large piece of gold like a bar, you can vouch for how suprisingly heavy it is.

2.107 4.26 * 10 L

2.115 x = z/(y-2)

2.124 So you lose minimal heat to the environment. Without insulation, your tempetature measurements for a bomb calorimeter will be low, giving you incorrect data to calculate the energy released by the reaction.

Also I promised you a link to that guy that lit a grill using liquid oxygen, here it is! Scroll down about halfway to see the pictures, there are multimedia files too.

Greek prefixes

2006-08-30T23:20:00.000-05:00

This wikipedia page has everything you need to know about SI prefixes. Don't be afraid to look for things online. You can look up additional info on wikipedia about scientific notation also! Give it a try!

Chemistry homework

2006-08-30T22:58:00.000-05:00

2.56) see glossary, though a measurement can be simultaneously accurate and precise, the words don't mean the same thing

2.58) Accuracy is poor but precision is good.

2.65) plus or minus 50,000 years

2.76) (a) 1, plus or minus 0.0005 kg (b) 2, +/- 0.000005 m (c) 3, +/- 0.5 L (d) 4, +/- 5 x 10^-7 m (e) 2, +/- 5 x 10^4 km

2.78) (a) 5. cm (b) 4.6 m^2 (c) 1.0000 x 10^4 J (d) 1. x 10 mm^2

Chapter 1 Homework Assignment and Answers

2006-08-26T10:42:00.000-05:00

Your homework assignment is found on pages 21-23 of your text. You are to answer questions 21, 29, 34, 49, 56, 62, 68, 81, 83, amd 95.

21.) Do not be too hasty in casting your judgement, such a technology could be tremendously useful. Consider costs and benefits carefully in your reasoning.

29.) This is an example of a question where looking beyond the text is useful. Wikipedia searches of sodium and iron shows that their symbols are derived from their latin names, natrium and ferrum respectively.

34.) Uranium, Plutonium, Cesium, Barium, Fluorine, Silicon

49.) Mothballs undergo sublimation at room temperature and pressure. This is because they are primarily made of 1,4-Dichlorobenzene. Click on the name to learn more!

56.) This is a chemical property of white phosphorous. Chemical properties of a pure substance like white phosphorous are the way it bahaves when combined with other pure substances, in this case, oxygen.

62.) Bias is a big one. If you believe a certain result will be achieved you will be more likely to misinterpret observations. Also, flaws in the design of an experiment will give flawe data for analysis.

68.) (a) mixture (b) mixture (c) compound (d) compound (e) elemental substance

81.) A chemical change. What actually is occurring is pretty interesting. At low temperatures and/or high pressures the NO2 moleules will dimerize to N2O4 molecules. Look at this for more information.

83.) One word. Magnets.

95.) NaCl

Welcome to the Blog!

2006-08-25T00:15:00.000-05:00

This is where I will be posting information about the chemistry class. I will also link to things I think you will find helpful or interesting. If you have any questions, you can use the comments feature to contact me. If you are posting anonymously, be sure to include your name so I know who you are.

Helpful online tutorials!

2006-04-17T21:09:00.000-05:00

Check out this site for help in understanding solutions.

The rest of the chapter 12 homework answers

2006-04-17T20:57:00.000-05:00

129. (a) Ba + 2OH --> Ba(OH)2 (b) 38.7mL, 23.4mL (c) 45.5mL, 27.5mL
131. (a) 3Pb + 2PO4 --> Pb3(PO4)2 (b) 10.8g (c) .355 M PO4
133. (a) H + OH --> H2O (b) .05782 M
136. The temperature will stop rising when the phase change is occuring, that is the desired temp
138. evaporation, condensation
146. 40.5g glucose
149. 80.8 degrees C, 4.14 degrees C

Some of these were a little involved. Try your hardest to get them correct. Come to me tommorrow and Wednesday with questions on how to solve selected questions.

Some Chapter 12 Homework answers.

2006-04-17T18:35:00.000-05:00

117) The # of moles of solute
121) a.) 25.0g b.) 12.0g c.) 226g
123) Add 50.0mL of alcohol to a 1.00L volumetric flask. Add water until the solution volume is 1.00L.
125) 4.50M
127) We mean that the solute particles become intermingled with the solvent by moving in a random, zigzag manner.

Chapter 12 Quiz Thursday!

2006-04-17T18:14:00.000-05:00

Tommorrow we will cover colligative properties. Wednesday we will hear some presenters and I will answer your questions. Check here tonight for homework answers.

Vocabulary Quiz redux tommorrow!

2006-03-29T21:17:00.000-06:00

Howdy Folks!

Here are the short form answers to tonights homework problems.

11.72) 200 degrees Celsius
11.77) a.) 30.0g/mol b.) CH3 c.) C2H6
11.84) The volume will increase
11.100) 8.22 * 10^-2 Latm/molK
11.118) Gas molecules are not held closely together by intermolecular forces, therefore their chaotic movements will cause them to fill any empty space. Solids and liquids are condensed phases, held together by intermolecular forces such that they cannot expand their volume to fill a space.

Good luck tommorrow! Also, after the quiz, I will take questions on chapter 11, so come with some ready.

Check This Out!

2006-03-29T15:09:00.000-06:00

Follow this link to see a neat interactive flash applet showing the relationship between temperature, volume, and the pressure of an ideal gas. Use the temperature and volume slides to see the effect on the pressure gauge. Notice the pressure of 1 mol of gas at 273.15K confined to 1 liter of space.

You may also find this link helpful. Look around

This isn't so hard, is it?

2006-03-28T17:21:00.000-06:00

Howdy folks. Here are the short form answers to tonights homework.

11.60) .166g/L, 1.66 * 10^-4g/mL
11.66) 10.7atm
11.68) 44.8L, 44.8L
11.70) 311L O2, 622L H2
11.105) False, the properties of an ideal gas depend on the amount rather than the mass of the gas present.

Remember, the vocab quiz returns on Thursday. Also, the chapter 11 quiz is on Friday. To adequately prepare for this Friday's quiz, you will need to have mastered all the assigned homework questions as well as the example problems within the chapter. I recommend working additional problems from those at the end of the chapter. Also, there will be no constants or conversions provided on the test; you are expected you to memorize them. Send me a message if you would like a special time to meet with me. Otherwise, I'll be in the great hall tommorrow at 7:30Am. Make the most of your opportunities for assistance.

Progress Quiz Tommorrow - That means Tuesday!

2006-03-27T21:01:00.000-06:00

Hey folks, here are the answers to tonights homework.

11.40) Inverse
11.42) V=(nRT)/P
11.49) 1.00 * 10^-3 mol
11.53) a.) 1.6 mol air b.) 45g N2, 9.9 * 10^-2 lb
11.54) Ideal gases are assumed to experience absolutely no attractive intermolecular forces.

Good luck on tommorrows progress quiz covering sections 11.1 and 11.2. Also, the vocab redux will be on Thursday and the chapter 11 quiz will be on Friday. See me before school if you need help. If you can't see me then, talk to me and we will arrange something.

1st progress quiz tommorrow

2006-03-23T19:48:00.000-06:00

Hello everyone. Here are my answers to tonight's homework so you can check your work.

8.123) 1.16g H2O, 3.09g CO2

8.143) 17.4g CF4, 7.92g HF

8.154) a.) coefficients: 1, 2, 3, 4 b.) 46.34g N2O4, 32.27g N2H4

Remember to read section 11.1 for tommorrow. Good luck on the quiz!

Some Updates

2006-03-05T22:59:00.000-06:00

Hello class. I believe I have fixed the blog so even non-registered individuals can post comments. Also, I have set up a system that should speed up my acknowledgement of class comments. For presenters desperate for sources, A message I received earlier today has softened me towards encyclopedic and web sources. If you decide you need to use these, make sure you document well.

For Monday

2006-03-03T17:04:00.000-06:00

Be sure to reread chapter 8 to understanding. The picture is a hint at the concept I want you to get a firm grasp of. We will have a brief quiz on Monday after the presentations. Have a good weekend!

"Office Hours"

2006-03-02T22:55:00.000-06:00

Remember, I will be in the Great Hall by 7:30 every morning from now on. Arrange something with me the day before in class and I can meet you earlier.

Also, we have been talking about significant figures a lot. Follow this link to a helpful tutorial. I reccommend every try it.

See you tommorrow.

Quiz Friday!

2006-02-22T15:01:00.000-06:00

Today, you were introduced the the several kinds of nonmolecular solids. Make sure you understand how they differ from molecular solids. I will want you to be able to identify substances as one or the other on the Chapter 10 test.

While anything that appears in chapter 10 is fair game, the topics covered by your homework assignments will certaintly appear on the test.

Definition of Terms - Make sure you have the definiton and understanding of all the terms printed in bold in chapter 10.

condensation
vaporization
boiling point
freezing point
condensed phases
London/dispersion forces
Hydrogen bonds
nonmolecular solid
network solids/network covalent solids
metallic bonds

Key points:
-the relationship betwwen the amount of energy in a substance and its phase, the overview at the bottom of p. 369 makes this especially clear
-the relationship between dispersion forces and the size of molecules or atoms
-why some molecules experience hydrogen boding and others don't
-the consequences of hydrogen bonding in water
-hydrogen bonding as it is related to DNA
-the difference between molecular and nonmolecular solids, their properties like melting points and conductivity
-the differences between Ionic solids, network solids, and metals

As you prepare, look to the example problems in the chapter. You will find that reviewing these as well as the homework problems you have already done will be helpful for the test.

If you have any lingering questions, leave a comment for me on this post. I will be checking the blog often on Thursday so you should not have to wait too long for an answer. Good luck with your studying.

Hydrogen Bonding

2006-02-17T11:37:00.000-06:00

Yesterday, I spoke to you all about hydrogen bonding, especially in water.

You may find this flash quiz helpful in clarifying the differences between different kinds of bonds.

We spent time looking at water. Follow this link to see another flash animation that shows you more about it. It will also give you a preview into the nature of acids and bases.

As an example of some of the more unusual behaviors that result from intermolecular forces, thake a look at this video of a simple water and cornstarch solution being shaken. Want to know more? Go to wikipedia and search for shear thickenong fluids.

Thats it for now. I hope you take the time to study your textbook during this long weekend. See you all on Tuesday!

Welcome Students

2006-02-14T17:52:00.000-06:00

I created this blog as a virtual meetingplace for our class. Here you will have an opportunity to get help, ask questions, and make comments. This morning I explained why I feel it is important that you give your best effort in this course. I have every confidence that each one of you will be able to master this material.