Changes in Attitude, Latitude, and Phases

The weather this week really helped increase my study time. If I hadn’t had a dog to walk (or West Wing on Netflix) I probably would have finished the entire Chemistry section.

Energy can be put to many uses and this lesson was about using it to change phases of matter. We can calculate the energy (q) , or heat, required to change the temperature of any material with a simple equation:

q = (m) x (Cp) x (Change in Temperature).

Cp is a constant value related to the material, specific heat, and m is the amount of material, or mass. In other words, temperature changes linearly with heat, which is obvious and beyond boring.

What gets interesting is the action during phase changes. As the energy changes, there is no corresponding change in temperature. Boiling water will stay at 100 degrees Celsius and a slushy ice mix will stay at 0 degrees no matter how much heat is added. The temperature does not change because all of the energy is being used to pull apart the intermolecular bonds which, like bad habits, are tough to break.

The energy needed to muster through a phase change is ‘heat of vaporization’, ‘heat of fusion’, or sheer will power. It is substantially higher that what’s needed to change temperature. Only after all the ice is melted or all the boiling water is evaporated will the temperature once again rise in a linear but boring fashion.

There are two simple equations:

q = (m) x (heat of fusion) when moving from a solid to a liquid and

q = (m) x (heat of  vaporization) when moving from a liquid to a gas,

and I am struck by two simple truths:

1. It takes a lot less energy to change outwardly than inwardly.

2. Transformation starts at the smallest level and for a while there are no signs.

Next Up: The Perfection of Gas and the Greatness of Organic Compounds

Related Articles:

Energy, Balance, and Astrology

When was the last time that you were so enthralled that hours passed like minutes?

The Principal and Science Chair of Rockhurst High School allowed me to to observe an afternoon of chemistry classes this week. Michael Sullivan taught the same subject to three different classes (AP, Honors, and General) with such a variety of techniques that I lost count. It was equal parts push, wait, argue, understand, noise, silence, chaos and clarity. The pace was blinding. The energy was off the scale. The jokes, mostly from the students, did not stop. Correct answers were celebrated with desk pounding and wrong answers were acknowledged with forehead smacks. The young men came in small groups discussing local sports, NHS events, and Schrodinger’s cat. They left arguing the best titration techniques and the quickest way to determine if a reaction is endothermic or exothermic.

I was also captured this week by the concept and mechanics of Oxidation Reduction reactions. It is not an overstatement to say that every aspect of our lives is governed by the behavior of electrons. In many reactions, electrons stay with the atom that brought them, but in Redox reactions they jump ship, sometimes in droves. This flow creates electricity and this knowledge led to the invention of batteries and the field of Electrochemistry.

Unfortunately, the mechanics of balancing Redox reactions did not flow as easily as the concept, but my Libra nature would not rest until I mastered the 10-12 steps. I used Kahn Academy, two additional Chemistry textbooks, and even Chemistry Essentials for Dummies. At the end of the week, I could take apart molecules, describe the flow of electrons, add water or hydroxide as needed, and then finally put them all back together again.

Let the desk-pounding commence.

Life, Death, and Chemistry

Look around – can you imagine how many chemical reactions are happening before your eyes at this very moment? Some materials are synthesizing and some are decomposing. Some compounds are swapping molecules and some may combust. Without these reactions and our ability to predict them, there would be a smaller staff at Downton Abbey, tonic would stay fizzy, nausea would last, and the New Year would be quiet.

The most important example of synthesis occurs when hydrogen and oxygen molecules combine to make water. This is as simple and profound as creation itself. A less inspirational example of synthesis is the formation of tarnish that occurs when silver reacts with sulfur in the air to make silver sulfide. Chemists call this 2Ag + S —> Ag2S and Lord Grantham calls it a steady job.

A sad example of decomposition is the spontaneous decay of carbonic acid (H2CO3) into carbon dioxide (CO2) and water. This is why that large bottle of tonic that you have been saving for the summer G&T’s may ultimately disappoint: H2CO3 ——> CO2 + H2O.

The most interesting reactions happen when compounds swap, or replace, molecules to form new substances. Hydrochloric acid (HCl) in the stomach makes us queasy until calcium hydroxide (Ca(OH)2) arrives. Oh what a relief it is when the acid is neutralized into two products that are much easier on the stomach: calcium chloride (CaCl2) and water,  2(HCl) + Ca(OH)2 ———> CaCl2 + 2(H2O).

For sheer drama, however, no reaction can match combustion. Fireworks are made with gunpowder that produces  heat and noise and metals that produce color. Copper shows blue, lithium and strontium red, and magnesium and aluminum are white when combusted. Combustion reactions produce much more energy than is required to start them and they need a lot of oxygen. Drama turns to danger when materials spontaneously combust, which happens when enough heat is generated by the reaction to ignite the materials at hand. This can happen with the right combination of microbes, moisture, heat and hay.

The laboratory of my life got a lot more reactive this week as I am making plans to use my favorite Christmas gift:  a Chemistry Set with enough equipment and reagents to conduct 333 experiments. My husband (aka Santa) has offered to help me set up an area in the garage and has even volunteered to be my assistant on the condition that I call him ‘Igor’. It’s all about the chemistry.

Will You Be My Neighbor?

My new glasses arrived this week. Let’s hope my spelling improves.

This week’s lesson was The Periodic Table. And with that sentence, I just lost most of my readers. Those of you still with me – imagine the vague underlying sense of discontent that haunted the chemists all through the 1860’s as they kept discovering elements, 63 in all, but without hope of reaching a greater understanding.

I used to work for a scientist who often said “Simple is best, unless it’s wrong.” Dimitri Mendeleev created the first Periodic Table simply and correctly by arranging the elements in ascending order of atomic mass. In doing so, he unlocked a powerful secret about those 63 and all that came after. The elements had a pattern and it was a pattern of eights. 

Just like my new glasses, Mendeleev’s list made everything in the world a little clearer. The elements suddenly looked like neighbors, grouped together by common interests and behavior. Holes in the list were simply houses under construction waiting for germanium, gallium, and scandium to arrive.

This begged a much larger question: What other neighborhoods were out there and just how large was this city?

Next Up: Inside The Great City

Are you ready for the country?

At 55 I have left corporate life and the city of Chicago behind. I want to use my love of chemistry and my engineering degree outside of the cubicle farms of the world’s largest oil company. I have moved, along with my husband, horses, dog and cat, to the real farms of rural Missouri.  As Neil Young wrote; “Because it’s time to go.”

I have limited platform skills, an unremarkable voice, and no classroom experience. However, I have organization skills and a good work ethic so that will have to suffice. Today I enrolled in the program offered by the American Board for Certification of Teacher Excellence (ABCTE) because it is on-line and recognized in the state of Missouri.

I am writing this blog for two reasons:

1. to help me reflect as I learn about teaching

2. to connect with others on this path.

Next step: Orientation.

Getting to Know You

Getting to Know You