Sunday, May 31, 2009

Chemical Conversions

During Cubby’s trial (see my previous post) I listened to a lot of testimony from a bunch of chemists. And of course Cubby is a chemist, and I can’t avoid listening to him day and night.

One of the things the chemists talked about was the idea of conversion of “stuff” when a chemical reaction takes place. The DA had suggested that explosives poisoned or polluted the ground when they were set off. However, the experts disagreed.

Chemistry professor Ken Williamson explained that a successful explosion converts substantially all the solid explosive into gas and energy. There’s little or nothing left on the ground. That got me thinking . . . what are some other examples of chemical conversion we see in daily life but never really think about? Allow me to present a few here . . .

Insect Conversion

When a bug flies into your electric zapper, you witness a reaction that takes electricity plus solid matter (the bug) and converts it into sound and light energy, a mix of gases, and debris. Experts believe that approximately 40% of the original insect mass remains as solid debris on the ground beneath the zapper, making this a pretty inefficient reaction.

But it’s nowhere near as bad as the next one . . .

Gasoline conversion

That’s what happens when you drive your car. The gasoline in your tank reacts with the outside air within the engine. When that happens, energy is released. Some propels the car down the road. Other energy is wasted as heat. And then we have the chemicals that come out of the reaction . . .

You read a lot about emission control in cars, where pollutants are measured in parts per million. We’ve come a long way in controlling those byproducts – hydrocarbons, carbon monoxides, and oxides of nitrogen. But the biggest polluter of all is totally unregulated, even today. That’s the greenhouse gas, CO2, which is now accepted as a key player in global warming.

When gasoline burns, its carbon and hydrogen separate. The hydrogen combines with oxygen to form water, and carbon combines with oxygen to form carbon dioxide (CO2). Raw gasoline is about 87% carbon and 13% hydrogen by weight. That means there’s about five and a half pounds of carbon in every gallon of gas.

When burned, each atom of carbon from the gasoline combines with two atoms of carbon from the air to make CO2. Since oxygen molecules are a bit heavier than carbon molecules, the result is twenty pounds of CO2 for every gallon of gas that’s burned.

That’s a lot of CO2, isn’t it? Three or four hundred pounds for every tank of gas.

Propane is better. Propane only makes twelve pounds of CO2 per gallon burned. So you can feel good about using your gas stove instead of your car, whenever you have a chance.

Coal is worse. And that’s what’s burned in many of our power stations.

I hope you’ve enjoyed today’s lesson in applied chemistry.

Now for a public service announcement . . . .

I will be speaking at the Agawam Public Library this Wednesday evening at six. They are opening a new autism resources section. I hope to see some of you there, and when you come, I’ll be happy to point out the chemistry section where you can look up reactions on your own.

7 comments:

SewDragonDesigns Embroidery said...

I have often wondered...if people feel that burning coal is so bad...and coal produces our electricity...then how is putting sooo many more electric/hybrid cars on the road any better?? Do people not think about all of the down process? Where does the electricity come from?

Or do people just see it as not using the gas, and the thought process stops there?

Eric said...

A friend of mine has a Morgan Plus 8 powered by propane, and I love it! Burns clean, and we can fill up at the local RV store where most campers are filling their trailers. Kind of neat to drive a car that gives off mostly water vapor. Although pound for pound gasoline is a more efficient means of power, I do like propane.

sylvia said...

what about the "chemical conversion" of alcohol (such as champagne, scotch, etc.) in one's system after ingesting.

Richard Levangie said...

Abbie @ Sew Dragon:

Actually, that is a common misconception. Burning coal is sending us to hell in a hand basket, but running a plug-in hybrid (PHEV) or an electric car (EV) with energy from a coal-fired power plant produces far fewer CO2 emissions overall than running a car on gasoline. A lot of variables go into the calculation, but using an EV or PHEV will cut your emissions by 75 percent.

But you're right. Ideally, we don't want to run our cars on coal, but on wind, solar, and wave power. But here's where it gets interesting. PHEVs and EVs will help cut the emissions at power plants, too.

Think of EVs as thousands and then millions of mobile battery units. Adding EVs will help smooth demand and make it much easier to add renewables to the grid. Using sophisticated Vehicle-to-Grid (V2G) communications, electric cars will be able to provide reserve power to the grid when demand is high, and recharge overnight when utilities have excess energy, and nowhere to put it. It’s also expected that when EV batteries reach their end of life, they can be employed for years at wind farms and the like as backup power supplies.

Climate change is coming hard and fast... We don't inherit this world from our ancestors, we borrow it from our children.

Full Soul Ahead! said...

I like to think of thought conversions and how new understandings change the chemistry in the body,thus changing the actions of a person, and his/her effect in the world.

Woof!

Bill said...

I like this "autism section to the library" thing. Hmmmm. Very very good. Thanks for this idea and the chemistry and I promise not to zap too many bugs at home. I hate being inefficient.

Kanani said...

Hmm....that's a lot of thinking, John.
Thanks for stopping by my blog.