Thermochemistry


Green Gasoline: Fuel from Plants
February 2010 (pp 13–15)

Author: Michael Schirber

Chemistry Connections: Bonding, Organic/Biochemistry, Reactions, Thermochemistry

Description: Describes how molecules, like cellulose, found in plants like switchgrass and plant “leftovers” like corn stalks, can be made into gasoline. Uses lots of graphics to explain the use of zeolite catalysts in the process of stripping oxygen atoms from carbohydrate molecules to make hydrocarbon molecules that, in turn, make gasoline. Distinguishes green gasoline from biofuels like ethanol. Describes benefits of green gasoline.

Hollywood’s Special Effects—How Did They Do That?
December 2009 (pp 5–8)

Author: Diana Lutz

Chemistry Connections: Bonding, Organic/Biochemistry, Reactions, Solids/Liquids/Gases, Thermochemistry

Description: Describes how various special effects are created for movies, including fake snow, fake skin, fire and explosions. Some chemistry is detailed to explain how the materials are produced.

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The Olympic Flame: Chemistry Held High
October 2008 (pp 4–5)

Author: Brian Rohrig

Chemistry Connections: Organic/Biochemistry, Reactions, Thermochemistry

Description: Describes the history of the Olympic torch, and its 135-day relay trip to Beijing for the 2008 Olympics, which included an underwater portion and a trip up Mt. Everest. Then discusses the chemistry of the torch itself, including its composition and the many different fuels used in the torch over the years. Chemistry includes equations for combustion of propane and ammonium perchlorate (for the underwater part of the trip).

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The Chemistry of Marathon Running
October 2008 (pp 6–8)

Author: Brian Rohrig

Chemistry Connections: Organic/Biochemistry, Thermochemistry

Description: Describes the author’s trials and tribulations running a marathon. Discusses aerobic and anaerobic respiration, the different fuels the body uses – carbohydrates (glucose, primarily glycogen), fats and protein – to fuel its muscles, and how the fuel changes with varying degrees of exercise. Article shows structural formulas of glucose and glycogen.

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Sniffing Landmines
April 2008 (pp 7–9)

Author: Sarah Vos

Chemistry Connections: Organic/Biochemistry, Reactions, Thermochemistry

Description: Discusses the use of trained dogs to sniff out landmines, and the need for both the dogs and handlers to be well trained. Says TNT (trinitrotoluene), the explosive of choice for landmines, can release DNT (dinitrotoluene) vapors, which dogs smell. Compares efficacy of sniffing dogs to metal detectors. Also covers research being done by military and academic groups to produce detectors that work the same way dogs’ noses do. Formulas for TNT and DNT, and equation for detonation of TNT are given.

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Captivating Chemistry of Candles
December 2007 (pp 4–7)

Author: Brian Rohrig

Chemistry Connections: Thermochemistry

Description: Gives a brief history of the chemicals from which candles were made, including modern-day paraffin. Explains the chemistry of combustion with special attention to the reaction zones, emissions and temperatures found in a candle flame. The role of convection and radiation in burning candles is also explained.

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Hindenburg: Formula for Disaster
December 2007 (pp 8–10)

Author: Tim Graham

Chemistry Connections: History/Biography, Solids/Liquids/Gases, Thermochemistry

Description: Details the story of the burning of the Hindenburg with emphasis on the structure of the ship and the hydrogen used to keep it afloat. Examines the causes, actual or theorized, for the event. One theory, the incendiary paint theory, is described in detail. The theory suggests that the sealant that coated the Hindenburg was made of iron (II) oxide, aluminum and cellulose acetate—all flammable chemicals and this the root cause of the fire, not hydrogen. Examines film of the fire and emphasizes reaction rates in discussing the theories.

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NASCAR: Chemistry on the Fast Track
February 2007 (pp 4–7)

Author: Brian Rohrig

Chemistry Connections: Solids/Liquids/Gases, Thermochemistry

Description: Describes the chemicals that make up NASCAR racing cars, from Lexan windshields, to Kevlar and NOMEX driver’s helmets, to the elastomer bladder lining the fuel tank. Also describes the structure of the engine and the combustion process used to power the cars. Special attention is given to methanol as the fuel and to octane ratings for fuels. Tires, rubber and traction round out the article.

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Thermometers
December 2006 (pp 14–17)

Author: Brian Rohrig

Chemistry Connections: Thermochemistry

Description: Details the history of establishing different temperature scales (Fahrenheit, Celsius, Kelvin) and early thermometers to record. Additional types of thermometers (IR, bimetallic strip, swallowed signal emitter, cooking “pop-up”) are described

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Salting Roads: The Solution for Winter Driving
February 2006 (pp 14–16)

Author: Doris Kimbrough

Chemistry Connections: Bonding, Solids/Liquids/Gases, Solutions, Thermochemistry

Description: Discusses freezing point depression and ions, compares salt to other de-icers in terms of number of particles formed when they dissolve. Also shows phase diagram for salt-water mixture. Describes new technology that also addresses highway safety in wintry conditions.

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The Amazing Drinking Bird!
October 2005 (pp 10–11)

Author: Brian Rohrig

Chemistry Connections: Bonding, Equilibrium, Solids/Liquids/Gases, Thermochemistry

Description: Describes what a drinking bird is and how it works. Explains the science behind the bird’s actions: evaporation of water cooling the top glass bulb, which lowers vapor pressure; greater vapor pressure at the bottom forces liquid up the tube until bird gets top-heavy and tips; liquid empties from tube, allowing pressure in two bulbs to equalize; process begins anew. Sidebar provides 5 additional experiments (extensions) to try with drinking birds.

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Carb Crazy
October 2004 (pp 6–8)

Author: Brain Rohrig

Chemistry Connections: Organic/Biochemistry, Thermochemistry

Description: Explains the chemical structure of different types of carbohydrates and their role in cellular respiration. Also explains the relationship of carbohydrates and blood sugar. Examines low-carb diets and how they work and how low-carb diets lead to ketosis, the conversion of fat to ketones. Offers pro and con research on the value of low-carb diets for teenagers.

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Activity: Cloud in a Bottle
October 2003 (pp 16–17)

Author: Bob Becker

Chemistry Connections: Equilibrium, Solids/Liquids/Gases, Thermochemistry

Description: This activity description details how to create clouds in a soda bottle through phase changes and the factors responsible for the creation—condensation of water vapor through pressure changes that create a temperature change.

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Chemistry in the Sunlight
October 2003 (pp 22–24)

Author: Jeannie Allen

Chemistry Connections: Organic/Biochemistry, Reactions, Solids/Liquids/Gases, Thermochemistry

Description: Positive and negative effects of ozone in our atmosphere—blocking UV radiation, negatively affecting biological tissue. Sources of ozone—volcanoes, burning fossil fuels. Additional “pollutants” (volatile organic compounds, VOC, and nitrogen oxides, NOx) and their effects are described.

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