Blog 11.1 Table J and the Activity Series of Metals [Due Wed May 23rd]

Blog Questions:

1.      The solutions you used were all nitrate solutions. For example, the silver ion solution (Ag¹⁺) is really a solution of silver nitrate (AgNO₃). The complete REDOX equation for the reaction between magnesium metal and silver solution is as follows:

         

              Mg_(s)    +    AgNO_3(aq)     -->    Mg(NO₃)_2(aq)   +    Ag_(s)

a) The nitrate ion is known as a “spectator ion”.  Explain why you think this name is appropriate:

b) In the reaction between magnesium and silver solution, what is oxidized

What is reduced?  

2. Propose a rule that predicts whether or not metal X and metal ion Y⁺² will react, based on Table J.

3.  Answer the two “lab questions” from page 1 of this lab:

1.    What is an “ACTIVity series” and how does it relate to what I already know about the behavior of metallic and non-metallic elements?

2.   How is an activity series used to predict (or explain) which metal (or non-metal) is more reACTIVE than another?

4. History of Metals

Currently there are 86 known metals. Before the 19th century only 24 of these metals had been discovered and, of these 24 metals, 12 were discovered in the 18th century. Therefore, from the discovery of the first metals, gold and copper, until the end of the 17th century, some 7700 years, and only 12 metals were known. Four of these metals, arsenic, antimony, zinc and bismuth, were discovered in the thirteenth and fourteenth centuries, while platinum was discovered in the 16th century. The other seven metals, known as the “Metals of Antiquity,” were the metals upon which civilization was based. The first 4 had been discovered and were in use before cultures had developed the ability to communicate in writing.  They are referred to in the oldest written documents we can find (like the book of Genesis in the Bible, as well as ancient Egyptian, Phoenician and Babylonian texts).  These seven metals were:

1.     Gold, 6,000 BC

2.     Copper, 4,200 BC

3.     Silver, 4,000 BC

4.     Lead, 3,500 BC

5.     Tin, 1,750 BC

6.     Iron, 1,500 BC

7.     Mercury, 750 BC

On Table J, the elements above H₂ are prone to oxidation in the air, and are therefore unlikely to be found in pure form on the Earth’s surface.  Rather, they are in compounds called “ores” which are metal oxides, like Fe₂O₃ (iron ore).  Why do you think gold, silver and copper were discovered so long ago by humans, but the other 4 metals were discovered later?

 

5. https://www.e-education.psu.edu/files/matse081/animations/lesson04/u04_metalWork.html

A significant advance in human civilization occurred when humans discovered how to extract copper from copper ore.  When mixed with tin, the alloy is called bronze and is harder than either metal separately.  Go to this website.  Check out two things:

·         How copper was “smelted” in ancient times.

·         How bronze was made.

 

Enrichment:

Ag¹⁺ is a very important ion in the history of Rochester, since it was the primary ingredient in George Eastman’s black and white KODAK film industry.  Research how this ion is used in photography.

Blog 10.1 Solubility and Curves

10.2 Section

1. Which samples are definitely polar?  How do you know?

2. Which samples are definitely non-polar?  How do you know?

 

3. From the data, what can you conclude about the polarity of ethanol?

 

4. Would you expect ethanol to dissolve in water?   How about in hexane?

 

5. Classify the following as non-polar or polar molecules.  Then, predict their solubility in each solvent.

	Type of Molecule	Solubility in Water	Solubility in Hexane
NH3
I2
HCl

6.  Why do ionic materials dissolve so well in water, but not in hexane?

Enrichment: Atmospheric gases such as oxygen, nitrogen and carbon dioxide are capable of dissolving in water. Make a prediction regarding how much you expect these gases to dissolve based on their polarity. See if you can find or think of at least one reason why oxygen and carbon dioxide need to be able to dissolve in water for aquatic life to flourish.

10.2 Section 

What things made a significant difference in how quickly the KClO3 dissolved. If you wanted to get something to dissolve quickly, what things can you do in order to make it happen. The more important question is: Why does this happen at the particle level, what does particle collisions and attractions have to do with this? Does surface area relate to this at all, and if it does what can you do to change that variable to make it happen quicker.

Describe how the terms unsaturated, saturated, and super saturated apply to the experiment. At what point was the solution saturated, and at what point was it unsaturated. I will tell you now that with potassium chlorate in this experiment, you never formed a supersaturated solution, it precipitated out before that happened.

ENRICHMENT: Find out how rock candy is made. I am sure you can find a recipe very easily, but I want you to apply this to chemistry using the vocabulary we have learned. This is a little more difficult task than just finding the recipe. If you want make it, try it, it is delicious.

Blog 9.2 LeChatlier's Principle (Due April 17th)

Blog 9.2: LeChatelier's Principle

Station One

 Explain the shift that happened when HCl was added.

 1.    Explain the shift that happened when the system was heated, based on the location (products side or reactants side) of “heat energy” in the reaction.

2.   Describe how the Delta H (heat of reaction) shows whether the reaction is endothermic or exothermic. Relate this to potential energy and also the + or - sign of delta H.

 3.    

a. What does Table F say about the interaction between Ag¹⁺ ion and Cl^1- ion?

b. From your observations about what happened when you added AgNO₃, what evidence do you have that the Table F interaction happened?

c. Explain the shift caused by adding AgNO₃.

Station Three Processing Question:

6.  In terms of pressure changes, explain how your observations help to make sense of the fact that a carbonated beverage begins to effervesce (release gas) as soon as the bottle is opened.  (A chemist might say the reaction “shifts to the right” as soon as the container is opened!)

ENRICHMENT: 

Chickens Lose Equilibrium…Problem Solved Applying Le Chatelier

By David B. Brown & John A. MacKay III

Chickens cannot perspire, so when they get hot, they pant.  This seemingly trivial fact led to a serious economic loss for egg producers.  In hot weather, chickens lay eggs with thin shells that are easily (and frequently) broken.  A little reflection shows that this is an inevitable consequence of Le Chatelier’s principle and the well-known carbon dioxide equilibrium system.

CO₂ (g)  <-->  CO₂ (aq) <--> H₂CO₃(aq) <--> H⁺ + (CO₃)^2-(aq) <--> CaCO₃(s)

(chicken breath) ------------- (chicken metabolism) ---------------------- (egg shell)           

When the chicken pants, the equilibrium is perturbed by the rapid loss of carbon dioxide.  Because this effect cascades through all of these equilibria, the effect is a loss of solid calcium carbonate, which ultimately produces weaker egg shells.

Ted Odom, while a graduate student at the University of Illinois, found the deceptively simple “solution” to this problem – give the chickens carbonated water.  Now the equilibrium has been perturbed in the opposite direction.  The addition of aqueous carbon dioxide shifts all of the equilibria to the right and results in stronger egg shells.  Moreover, the chickens seem to like the carbonated water, and there are rumors that they spend their spare time singing familiar singles about “spirit” and the “real thing.”  Philosophical questions about which came first are left to the reader, but in this case, at least, Le Chatelier’s principle comes before the egg (shell).

Questions:

1.)    What gas do chickens pant out?

2.)    When the [CO₂] decreases, which way does the equilibrium shift?

3.)    When the equilibrium shifts, what happens to the amount of the CaCO₃(s) (the egg shell) that is produced?

4.)    Explain why panting results in thinner egg shells.

5.)    What change could farmers make to assure thicker egg shells in hot weather?  How does this change take advantage of Le Chatelier’s principle?

Blog 9.1 Heat of Solution (delta H), Using Table I. Due Date April 5th (Thurs)

Post-Lab Questions: (Blog Questions)

1.)   Was your solution process endothermic or exothermic?  Describe the process using terms such as: direction of heat flow, system, and surroundings of the system.

 

2.)   What are the possible sources of error that cause a difference in the value that you got, and the value that was published on the reference tables (table I)? (Human or calculation error are not acceptable.)

 

3.)   How would your numbers for q, moles of solute, and ultimately ∆H (q/mole), be affected if…

a.)   The room temperature was 10^oC colder.  Explain.

 

b.)   You added less chemical, but knew the mass you added.  Explain.

 

c.)   You added 40 mL of water but thought you had added 50 mL.  Explain.

 Enrichment:  (1 pt)

In Florida, when the weather report is calling for freezing temperatures, orange farmers will mist the fruit trees with water overnight in order to prevent damage to the tree and fruit.  The water being sprayed on the tree freezes, but as it does so, this protects the tree from damage.  Explain why this works.

Blog 8.1 Hydrocarbon properties and uses (Due Thursday March 15th)

Hydrocarbons (alkanes, alkenes and alkynes) are very important substances that we use for many things. We drill for and pump crude oil which is a mixture of lots of different hydrocarbons. You need to answer these questions about hydrocarbons, you will have to do some research to be able to answer these questions. Please ignore the temptation to copy and paste your findings into your blog.

First answer these questions:

What is crude oil? What components are in the mixture of crude?

How to we separate the components of the mixture? What physical properties do we use to do that separation?

How do the properties of hydrocarbons change based on their size? How does this influence the boiling point of something small like methane compared to something large with 30 C's or more?

Research one or more of the following of interest to you.  Write 2-3 paragraphs summarizing your findings.

a.     The discovery of oil in the US and the location of the first drilling for oil ever done.

b.     How oil is drilled out of the ground.

c.      The extraction of oil from “oil shale” and “oil sand” deposits.

d.     The refining process used to extract particular components out of “crude oil.”

e.      The likelihood of finding natural gas, oil or coal deposits in Western NY.

f.       Why oil prices have been rising lately, and how the global oil trade is run.

Lab 7.3 Reactivity of Metals

1.  Answer the lab question on the first page of this lab.  CITE EVIDENCE FROM YOUR OBSERVATIONS! Make sure you explain thoroughly.

2.   Why do elements in the same column on the Periodic Table tend to have VERY SIMILAR properties?  Explain in terms of electron configuration! Use specific examples from your groupings.

3.   Describe what happens when an atom of sodium atom interacts with an atom of a nonmetal.  In your description, indicate:

a.   Whether the sodium atom loses or gains electrons,

b.   Whether the sodium atom becomes a positive or negative ion,

c.   The electrical charge of the sodium ion,

d.   Which noble gas sodium’s electron configuration becomes like,

e.   Whether the sodium atom becomes more or less stable as a result of reacting.

ENRICHMENT: 

The elements Li, Na and K are too reactive to be found in nature as pure elements.  Research how chemists obtain pure sodium in the form like we used in lab.

Lab 7.2 Periodic Trends Activity

These three trends are more challenging to explain, explain them:

·        Atomic radii trend going from left to right across a period.  The heaviest elements in a period have the smallest radii. WHY?

              ·        Electronegativity decreases when you move down a group. The larger the atom in the same group, the less it attracts electrons. WHY?

·        Ionization energies as you go from left to right across a period.  It kind of makes sense that it is harder to strip an electron from a metal than from a non-metal, but WHY is this so?

The key to explaining these trends is to figure out what “nuclear charge” is, and then to figure out what it has to do with these property trends.  Google will be a big help if you ask the right question in the search bar!  Good luck, and of course, talk with your teacher as needed!



Why do you think the trends are referred to as being "PERIODIC." Hint the word periodical is sometimes used with magazines and newspapers that are delivered at regular intervals.

Blog 7.1 Flame Tests and Emission Spectra

Conclusion:

1.  After seeing the spectra of various elements in this lab, why do you think an element’s spectrum is often called its “fingerprint?”   Explain using the terms ground state, excited state, and electron configuration.

2. Explain how a spectra is formed. Make sure to include the process and the steps that occur. This is important that you can describe what happens during the changes between ground and excited state, and how energy is released and absorbed.

ENRICHMENT:

1.  Research the discovery of the element Helium, and why it is given the name it has.

2.  Find out how astronomers use what is called a “red shift” or a “blue shift” to know whether a galaxy is moving towards or away from our galaxy.  To do this:

a)  Explain what blue shifts and red shifts are, and what they have to do with an element’s spectrum.

b)  Explain how the ratio of blue shift to red shift galaxies is used as evidence that the universe is expanding.

c)  Find out what Sir Edwin Hubble had to do with all this.  

Lab 6.1 Double Replacement Reactions

In our lab we looked at many different scenarios where a double replacement reaction either resulted in no apparent change, or the formation of a precipitate.

First, take a look at your predictions. Where they all accurate? If not explain which ones did not match up. See if you can figure out what happened. There was one trial that had results that did not match up with the expected prediction. Where you able to find it, which one was it? What do you think the insoluble product was, this will go against what table F tells us!!

Write a procedure on how to write a double replacement reaction. You can do this with bullets or paragraph form. The steps that you must have include: finding and writing the formulas for the products, balancing the reaction, and finding the precipitate. Describe theses steps (and more if you need them in detail, don't just give me a list of what I just gave you!!)





Precipitation reactions are very important in water treatment and purification. Find a contaminant that is removed from waste water before it is processed back into nature using a precipitation reaction (hint do a google search). See if this reaction is consistent with the information on Table F (it depends on the ion that is used). Sulfate is an ion that is often used to form precipitates, using Table F why is this a good choice.

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.