Lab 5.1 Rates of Reaction

Ok so the last experiment that we did really focused in on the reasons that a reaction will proceed at a certain rate. The way that you will need to think about this process has to do with particle collisions and how they influence how fast the reaction will happen. For a reaction to happen we need what is called an effective collision. This means that the particles have collided in such a way that there will be a chemical reaction. The changes we made in the lab, influence the number of effective collisions that were occuring.

The first thing that we did in the lab was try to make a plan so that you could determine how the lab would be done so that you could tell how changing each variable would influence what happened. Describe quickly what you did in the experiment. Include in this description why it was important that you controlled the variables in a certain manner. In the lab pre-assessment that you did we chose that student B was the one that had the best procedure to determine how a variable affected the rate. Why was his method the best? What would happen if you varied multiple variables at the the same time?

By changing the concentration of the vinegar, the temperature of the vinegar, and the amount that the tablet was crushed the rate of reaction was changed. Describe, using particle collisions why each variable changed the rate. Also describe if the results in your experiment were consistent with what you expected to happen. If they aren't, describe something that could have gone wrong in the process.

Enrichment: Do some online research and find an example of a real-life catalyst. Find out what changes in the reaction and how that has a significant influence on the rate of reaction. If you need help getting started catalysts are often used in industrial processes in order to make reactions more efficient. Also, you could look at enzymes and see specifically how they change a biological process.

Lab 4-2 Heating and Cooling Curves

Now that you have had the chance to digest the heating and cooling curve process a little bit, I am going to ask you guys to think about what happened in the process.

Paragraph #1: Write a clear procedure for what you did in this experiment. This may be in bullet and complete sentence form, or paragraph form. The blogs have been getting better, but the complete sentence issue is a must.

Paragraph #2: Take a look at the graph that you made as a result of the data that you collected. Identify the melting point of lauric acid from your graph. Identify the freezing point from the second graph that you made [many of you put the on the same axis, which is fine]. Are these two values the same (and should they be the same)? Explain how you determined the freezing and melting points from your data.

Paragraph #3: As you heat a substance to its melting point and through the phase change there are changes that occur in both kinetic and potential energy. Explain what kinetic energy is and when it is increasing during your heating curve and decreasing in your cooling curve. Explain what potential energy is, and also explain when it is increasing and decreasing in your curves.

Enrichment:

Lauric acid of course has an actual melting point. Find the actual melting point and compare it to your data. Calculate the percent error and predict a reason why you were high or low (the thermometers are accurate, so don't blame them.)

Find out more about lauric acid. Maybe what it is used for, or could potentially be used for, find its chemical formula, structure, anything relevant about the chemical. Reference the source that you used to find the information.

Blog 4.1 Having Fun With Air Pressure

Answer each of the following AND Explain!!! 

I am looking for you understanding of how and why the particles in the gases cause the change that you are predicting.

You will not receive full credit if you do not explain with complete sentences.

 

1. A decrease in pressure causes the volume of a balloon to _______________________.

                                                                                                  (increase, decrease or stay the same?)

2. Adding more gas to a bottle ____________________ the pressure in that bottle.

                                                       (increases or decreases?)

3. As the volume of a cylinder is increased the pressure will __________________________.

                                                                                                    (increase, decrease or stay the same?)

4. Increasing the pressure in a tire by adding more gas will cause the volume to _______________ .

                                                           (increase, decrease or stay the same?)

5. As the temperature of a closed container of water is increased the amount of water vapor  above the water causes a(n) _________________________ in vapor pressure.

                                          (increase, decrease or no change?)

6. As the air pressure above a liquid is increased by adding more air, the boiling point of the liquid will _____________________.  (increase, decrease, or remain the same?)

7. If a balloon filled with air is taken under water to a depth of 10 feet, it’s volume will ______________________ . (increase, decrease, or remain the same?)

8. The temperature of a beaker of boiling water will __________________ as more heat is  added.                                                                                  (increase, decrease, or remain the same?)

  

9. Hot air rises because it is _____________ dense the cold air around it.  

                                                  (less or more?)

10.  When heated, the volume occupied by air in a balloon  will ___________________________ .

                       (increase, decrease or stay the same?)

ENRICHMENT: 

Try to explain what happened to the tanker car shown in the pix, in terms of gas particle behavior.  The situation happened when some workers cleaned the tanker out with a hot water flush and then sealed the tanker car lid after doing their work in the middle of the day.  That night, the air temperature dropped down to the 35⁰F range.  The car did this sometime during the night.

Properties of Ionic and Covalent Compounds (3.1)

Conclusion:

 Respond to each item asked for on the rubric and answer the following questions.

1. List the general properties of ionic compounds. (hardness? conductivity? conductivity in solution? melting point?)

 

2. List the general properties of covalent substances. (hardness? conductivity? conductivity in solution? melting point?)

 

3. What types of elements combine to form ionic bonds? Explain what happens with electrons with this type of bonding.

 

4. What types of elements combine to form covalent bonds? Explain what happens with electrons with this type of bonding.

5. Why do covalent compounds lack the ability to conduct electricity as a solid or in solution?

 

6. Why do ionic substances conduct electricity in solution, but not as solids?

Enrichment:

Solutions containing ions are often called “electrolyte solutions.”  Research electrolytes and find out:

¨  Why drinks like Gatorade advertise that they contain electrolytes,

¨  What electrolytes have to do with you and exercising,

¨  How electrolytes are used by your body to transmit messages from your brain to your muscles,

¨  What is the electrolyte substance used by your body?

Post 2.2 - Bag of Ions and Periodic Table Chem Crunch

After completing these activities I am looking for you guys to communicate your understanding for the organization for the periodic table. So please consider the following [Bill Nye Reference]

In your own words describe how the periodic table is arranged, you may wish to include something about the groups and periods, electron configuration, valence electrons, and the different families.

For the second part, I want you to compare and contrast ions and atoms:

• What is similar about atoms and ions of the same element
• What is different about atoms and ions of the same element
• Why do ions form?
• How can you predict the charge on an ion by looking at valence electrons and location on the periodic table

Overall, I am looking for how well you understand these concepts, if you have any questions use your packets and notes and chem crunches, and don't be afraid to ask questions!!

Lab 2.1 Grouping of Elements

1.    Based on the information in your text on p158-160 (or another source that names the different groupings on the periodic table),  “Name” the groupings of elements that you created on the last page.

2.  Classify the four properties tested in this lab as either a physical property or chemical property.  Explain your thinking.

3.   a)  State what is unique about elements that are “metalloids.” 

b)  Identify any elements among our seven that are metalloids.

c)  List the names and symbols of all the metalloids. 

4.   When you look at a Periodic Table, you will notice that the seven elements we tested are all clustered near each other. 

State the trend that appears to exist:

a)  In terms of metallic character of elements, as you proceed from elements on the left to elements on the right in the Periodic Table.

b)  In terms of metallic character of elements, as you proceed from elements near the top to elements near the bottom in the Periodic Table.

ENRICHMENT:  Some elements, like lead (Pb), have symbols that due not seem to match their names.  Pb is derived from the Latin name for lead, which is “plumbum.”  This is due to the fact that this element was used in Roman times for making pipes for drinking water (“plumb”ing pipes).  There are 10 other elements like this.  Find one or more of them, and research why the symbol is what it is.

Lab 1-4 Physical and Chemical Changes

We have talked a bunch about physical and chemical changes now. What I would like you to do is to design a clear set of criteria that you can use to determine whether a change is physical or chemical.

In this process I want you to discuss the following:

• What types of changes are chemical and what types are physical? (Come up with examples for each)
• What types of evidence are you looking for in a physical change?
• What types of evidence would convince you that a chemical change has occurred?
• When you are stuck in a scenario where you are unsure, what other resources can you use to figure it out? A good example of this would be the sodium polyacrylate and water, what was it anyway?

Enrichment:

Find a video of a sweet physical or chemical change. Describe which it is. See if you can figure out how to embed a video into a blog post.

Lab 1-3 Separation of a Mixture

Hey Everyone, from reading your blogs it looks like you are getting the idea for the general outline and purpose of what we are trying to accomplish with the blog. If there are some comments asking you to add to your blog or edit it, please make the changes, your grade will reflect it.

For this experiment you need to write the normal paragraph summary outlining what you did. After you do that you need to consider the following:

1. Compare the amounts of iron, sand and salt that you had initially in your mixture to the amounts that you recovered. Were they all equal? Propose a reason for each of them being different than expected. I won't accept reasons stating that you measured wrong or did math incorrectly. I am looking for problems with the experiment.

2. How could you have made your separation better? For example: if you had sand left in your iron what could you have done to get it out?

3. Explain how you chose how many digits to round your final answers to.

Write a conclusion paragraph explaining how what we did relates to what we are currently doing in class. If you have further questions, this would be the place to ask the questions and address what happened.

Enrichment: Do a little research and find out the steps that are used to manufacture and purify a chemical. The important process here is the purification, because it directly relates to what we are doing in class.

Lab 1-2 Indirect Measurment

First in your blog write a summary of the experiment and your results.

Then: Answer these questions

1.     Some methods for finding the diameters and thickness are much better than others. Explain the limitations of using water displacement and a ruler to calculate the thickness.

2.     When calculating the actual thickness of the foil the number calculated will likely contain a large number of decimals. Can we be confident that this represents an exact measurement? Explain why or why not this is the case.

3.     Suggest some sources of error in how you conducted the measurements that might explain any error in your diameter value.

To conclude your blog entry, explain how you could use a method like the one in your experiment to solve another problem that might not have a clear cut answer.

ENRICHMENT: 

As a person who will soon be paying your way through life, learning to evaluate the “best deal” is an important skill so you can get the most value for your money.  Obtain information about the price and amount of foil in roll of each type of aluminum foil.  Use this information, along with the thickness value for each type of foil, in order to determine which type of foil gives more value.  You may choose to do this by:

a)     showing a mathematical way of figuring this out, OR

b)    describing in writing how you would figure this out. 

Prices:     HD: $3.79 for a roll 70 cm X 6 m

               Regular: $5.79 for a roll 40 cm X 15 m

Lab 1-1: Green Stuff

Ok, now you have completed your first experiment and have had a little bit of a chance to think about it.

The purpose of the lab blog is to do the thought processesing that goes along with the experiences that you had in the experiment.

Your blog post should be outlined as follows:

• A quick summary of the experiment, tell me what you did (a procedure) and what happened (your results). I am usually looking for roughly a paragraph here, you need to provide enough so that I can tell that you understood what you were doing.
• Answers to the lab questions, in this case they are:
• Explain how you can determine if a property of green stuff is a physical property, or a chemical property.
• Describe the different phases of matter of the chemicals (water is a chemical too) used in this experiment. Make sure to tell how solids, liquids and gases are different.

•  Describe how the material relates to what we have been completing in class. Also this is where you can pose questions that the lab made you think about, I like to see this stuff and respond to it.
• Enrichment Questions: I will at times pose enrichment questions, if you want to get 5/5 on all categories all the time, you will need to answer these. For this experiment, come up with an experiment that you would like to try with green stuff. Its name is copper (II) chloride if you want to do a search.

All in all I am looking for 3-4 paragraphs. I will read and respond to you for a grade. I will also be sending you a link so that you can view your progress in a spreadsheet. This will be similar to the one in the syllabus that we discussed on the first day of school.

Welcome to the Mr Evangelos Regent's Chemistry Class

Welcome Back!!!!

If you are checking out this page, then my guess is that you are a student or a parent of one of my 2010-2011 Regents chemistry students. This blog will be used to manage information this year to communicate home and to provide students with information that will help them as the year goes by. Data files will be hosted on my Rush-Henrietta teacher page which I will periodically provide links to.

I usually get asked about class materials this time of year. 

Here is what you will need for chemistry class:

A large 3-ring binder (2 inches usually works, some students have gotten 2 x 1" because it was cheaper or easier to carry around)

A calculator (scientific is best, if you already have one for math, just bring it to chemistry class also)

Kleenex: if every student brought a box at the beginning of the year we would never run out (the school doesn't provide it). If not we end up using paper towels, which are the brown rough type that are not friendly on the sick nose.

Writing instruments, loose leaf paper, normal everyday school stuff.

Contacting Me.

There are two very easy ways to contact me, one is through the phone the other is email:

Phone: 585 - 210 - 2436 (210-CHEM). This is a Google voice number, it can receive and send text messages and also voice calls. Most of the time if you call you will get a voice mail box. I will call back during a planning block, after school, or a time that you tell me is convenient.

Email: AEvangelos@rhnet.org  this is my school email, I answer emails from here promptly. If you have a question don't be afraid to ask.

Information Exchange.

I will be setting up a Google documents account where I can share student progress.You will be able to log in and look to see how you, or your student is doing. This is my first year using this tool, so we might have some bugs to work out but I am looking forward to being able to share information with you easily!!