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.