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. Why was your procedure effective at determining how each variable influence on the rate? What would happen if you changed 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 of Lauric Acid

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. Here are two graphs produced from Jake Eggleston and Nate Gillian's data.






Paragraph #1: 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 the above 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 #2: 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 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?)

Tell whether each of your predictions was accurate or not. This should take at least four sentences in order to say if you were correct, and then why or why not.

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.

Blog 3.2 Properties of Ionic and Covalent Compounds

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?

Lab 3.1 Modeling of Molecules

As we know, all matter is made up of little particles. 

When a sample of material is known to use covalent bonds, the material is said to be “molecular,” or in other words, the material is made up of “molecules.”  A cluster of HCl molecules is shown below.  Molecules have an electrical charge of zero.

 

 

When a sample of matter is known to use ionic bonds, the material is said to be “ionic,” or in other words, the material is made up of “ions.”  A cluster of Al³⁺ and O^2- ions is shown below.  Ions have electrical charges on them.

 

One way of knowing whether a material is using ionic or covalent bonds is to test its melting point.  It is generally true that molecular substances have lower melting points than ionic substances.  For example, HCl melts at -115^oC while Al₂O₃ melts at 2072^oC. 

1.  Decide whether you think the attraction between ions is stronger than between molecules, or visa-versa.  Explain what evidence you are using from the information above, in order to make a conclusion about this.

2.   When HCl molecules are melted, do we still have HCl molecules, or are the molecules broken down into H and Cl atoms?  Explain based on your understanding of whether the process of melting is a physical or chemical change.

3.  When ionic substances are melted, they can conduct electricity.  When they are solids, they can not.  Explain why this is so.

4.  Molecular substances do not conduct electricity in either solid or liquid form.  Why not?

ENRICHMENT:  Research what a “polar” molecule is.  Find out whether or not water molecules are polar.  Draw a set of 4-5 water molecules showing how they arrange when touching each other.

Blog 2.2 Bag of Ions and Periodic Table Activities

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]

PARAGRAPH ONE: 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.

PARAGRAPH 2: 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 [Due Friday 10/21]

Lab 2.1 Grouping of Elements

1.    Based on the information in your text on p158-160 (or your reading you completed for homework),  “Name” the groupings of elements that you created on the last page of the lab.

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 1-3 Separation of a Mixture [Due Wed 9/28]

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?

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 1-1 Green Stuff [Blog Due Friday 9/23]

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 processing 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.

Lab 1-2 Indirect Measurment [Blog Due Monday 9/19]

First in your blog write a one paragraph 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.     Suggest some sources of error in how you conducted the measurements that might explain any error in your diameter value. 

3.   Describe one problem you encountered in your experiment and tell how you overcame that problem. This could be related to question #2 above, or not.

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

Welcome to 2011-2012 School Year!!

Dear Students,

I am excited about getting the new school year started. Here is a little about me…..

About Me:

I was born in Rochester and grew up in nearby Honeoye Falls. I graduated from HF-L and from there went to Nazareth College where I majored in chemistry. I graduated and went back for an extra semester in order to student teach. After student teaching I got a job in the Greece School District teaching 7^th grade science for the second half of the year (it wasn’t for me). After that I got hired here at Rush-Henrietta and now it will be my fifth year here!! I just finished my Master’s Degree at SUNY Brockport!! My next step is going to be to apply for doctorate programs and likely become a teacher of teachers.

Family and Stuff

Some of my family is still here in Rochester. My parents moved from Honeoye Falls to Palmyra where they both work, so they are still in town. My little sister just graduated from Nazareth College as a speech pathologist. She just got a job in Orlando, FL and lives down there, I helped her move. I have no pets, but part of me wants to put together an awesome tropical fish tank. My older brother lives in Washington DC and my best friend lives in LA, I miss them both.

Non-School Stuff

I am big time into soccer. I played soccer at HFL and Nazareth. I still play sometimes at TSE or the Sportsgarden, but I am now mainly a referee. I college professional, and summer league games. You can see me on the rhinos games sometimes. I travel a lot of refereeing, all across the northeast. In the winter I ski, I also try to get on my mountain bike whenever I can. I am not a huge gamer, but in my occasional free time you can find me on my PS3 (rewryn).

About this school year

I look forward to this school year and have some goals. The main one is for everyone to get a better understanding of Chemistry. I also want to make you guys better problem solvers. You will get better by thinking analytically and working hard. I also want to help my students get ready for college. If I am not totally forth coming with information, it is probably because I want you to do the thinking. I do want you to ask questions and as we get to know each other you feel like you can ask the tough ones when necessary. I wish everyone a safe an successful school year and look forward to working with you this year.

 

Sincerely,

Mr. Andrew Evangelos

Blog 11.1 Corrosion of Metals [Due Monday 5/23]

1.   a)   Was the penny wrapped in steel wool (made of iron) more or less corroded than

unwrapped penny?

b)     Is this protection from corrosion by using the “coating” technique, or the “sacrificial metal” technique?

c)      The Statue of Liberty was becoming so weak from the corrosion of the copper that it was shut down and “refurbished” in the early 1980’s.  In the process, many iron bands were added to the inside of the statue, making direct contact with the copper.  These bands are now regularly checked and replaced as needed.  Explain why this chemical trickery works to prevent the further oxidation of the copper statue, based on Table J!

My father wrapped the wooden posts on his porch in a product designed to protect the wood.   The product is made out of painted aluminum.  He used iron nails (non-galvanized ones) to nail the aluminum sheets to the wood.  Now after 2 years of weathering, the places where the nails penetrated the aluminum are corroding and crumbling. 

 2.  Explain why this corrosion is happening, in terms of the two metals and Table J.

 

3.  Explain why this problem could have been prevented if the spots where the nails were put in had been sealed with caulking.

3.  Answer the two “Lab Questions” from page 1 of this lab.

Enrichment:

Two metals in contact with each other and moisture will react in what is called a “galvanic reaction.” 

Metal A will be oxidized by the action of oxygen and with the help of the moisture. 

         

                   A (s)  +  O₂  --> The oxide of A^x+  

The Metal B will be oxidized as well, but this happens as it tries to restore electrons to the first metal.

                  

                   B (s)  +  A^x+  --> A  +  B^y+

This process can be helpful (as in the case of a ship hull being protected) or destructive…

Based on the description of my father’s corrosion problem in the Conclusion section, decide with Metal is “A” and which is “B.”  Write the reactions shown above, using actual metals in place of A, A^x+, B and B^y+.  Make sure you pay attention to proper ion charges (Fe becomes Fe²⁺).