Humboldt State University ® Department of Chemistry

Richard A. Paselk

Science 331
Fall 2004 Lecture/Activity Office: SA560a
Notes: 30 August Phone: x 5719
Home: 822-1116
e-mail: rap1

Energy

Law of Conservation of Energy: Energy is neither created nor destroyed in chemical processes. The problem here of course is - What is energy? Energy is the capacity to do work. So what's work? Work occurs when an object (mass) is moved against a force. Some common forms of energy important to our study include:

Another form of energy we need to be familiar with is:

Note that these forms of energy are readily interconverted.

 

Matter

Last time we looked at some gerneral properties of matter, and explored the physical states of the non-radioactive elements. Let's look at matter in a variety of forms and try to deduce some thing about its make-up. Recall the states of matter.

 

States of Matter and Changes of State

Matter can exist in three states under earth-surface conditions:

A common form of matter exhibiting these states under lab conditions is water. Let's look at water starting in its solid state and observe its transitions. We'll use the following equipment:

So let's all melt some ice and observe what happens:

What can you say about what has happened? e.g.:

 

Matter and Atoms

Why do we think atoms exist?

Demo spectroscopes and gratings - rainbows vs. line spectra.


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© R A Paselk

Last modified 30 August 2004