Microsoft Word Basic Chemistry Vocabulary List doc

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Basic Chemistry Vocabulary List
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absolute temperature
: This is a temperature reading made relative to 
absolute zero. We use the unit of Kelvins for these readings.
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absolute zero
: This is the lowest temperature possible. If you remember that 
temperature is a measurement of how much atoms move around in a solid, 
you can guess that they stop moving entirely at absolute zero. In reality, 
bonds still vibrate a little bit, but for the most part you don't see much 
happening.
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accuracy
: When you measure something, the accuracy is how close your 
measured value is to the real value. For example, if you're actually six feet tall 
and your brother measures your height as six feet, one inch, he's pretty 
accurate. However, if your cousin measures your height as twelve feet, 13 
inches, he's not accurate at all.
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acid
: This is anything that gives off H+ ions in water. Acids have a pH less 
than 7 and are good at dissolving metals. They turn litmus paper red and 
phenolphthalein colorless.
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acid anhydride
: This is an oxide that forms an acid when you stick it in 
water. An example is SO
3
- when you add water it turns into sulfuric acid, 
H
2
SO
4
.
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acid dissociation constant (K
a
)
: This is equal to the ratio of the 
concentrations of an acid's conjugate base and the acid present when a weak 
acid dissociates in water. That is, if you have a solution of Acid X where the 
concentration of the conjugate base is 0.5 M and the concentration of the acid 
is 10 M, the acid dissociation constant is 0.5/10 = 0.05.
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activated complex
: In a chemical reaction, the reagents have to join together 
into a great big blob before they can fall back apart into the products. This 
great big blob is called the activated complex (a.k.a. transition state)
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