Welcome to Basic Chemistry

(CHEM 1005)

My name is: Eric Mechalke. I will be your instructor this semester.

My goals this semester are to:

Q: So what is chemistry?

A: The science concerned with the composition of substances and the changes substance undergo.

A: The study of matter.

Q: What is matter?

A: Any thing that has mass and occupies space.

Matter has measurable characteristics; weight, volume, temperature…density
(And we use these measurements as a means to study chemistry).

 

Let us look at some branches of chemistry

Organic chemistry
The study of substances that contain carbon.

Analytical chemistry
The study of what is in a sample (qualitative) and how much of it is there (quantitative)

Physical chemistry
The study of a substances structure, how fast substances change, (kinetics) and the role of heat in chemical change (thermodynamics)

Biochemistry

The study of chemical reactions in living systems

 

The Scientific Method

Science is both a methodical exploration and a logical explanation of the observations of that exploration. Rigorous, systematic investigations of nature.

An experiment takes place when one explores nature according to a planned strategy and makes observations under controlled conditions.

In addition to being a systematic investigation of nature, the scientific method requires proposing an explanation for the results of the experiment.

The initial proposal is often called a hypothesis.

In order for a hypothesis to become scientific theory, there must be much experimental evidence.

 

 

The Skeptical Chemist

"Scientific speculation is worthless unless it is supported by experimental evidence" Robert Boyle

(Robert Boyle is considered to be the founding father of the scientific method)

 

The Scientific Method

1. Perform a planned experiment, make observations, and record data.

2. Analyze the data and propose a tentative hypothesis to explain the experimental observations.

3. Conduct additional experiments to test the hypothesis. If the evidence supports the initial proposal, the hypothesis may become a theory.

 

SIR ISAAC NEWTON

Observation: All bodies fall

Hypothesis: Gravity acts the same on all bodies

Experiment: Measure the rate at which a body falls. Repeat for bodies of different masses.

g=32ft/s2

(Note here that Isaac Newton is said to have discover the "law of gravity" and in Newton’s experiment a measurement was taken and we now have this number "g=32ft/s2" which is the acceleration due to gravity. See below on how a theory differs from natural law)

Lousi Pasteur

Observation: Food spoils

Hypothesis: Microorganisms in the air are the cause

Experiment: Kill organisms with heat and seal from air. See if food spoils

How does a theory differ form natural law?

A theory is a model that explains the behavior of nature.

The atomic theory states that matter is composed individual particles. This helps explain the behavior of gases.

A natural law does not explain behavior, but simply states a measurable relationship

Many times a natural law is expressed as an equation.

Bolye’s law states: P1V1=P2V2

 

Careful Observation

(All of the below items are used much in science to ensure 'careful Observations')

Control group

(The control group is not subject to the same experimental varible as the test group)

Laboratory note book

(Good record keeping is a means of careful observation)

Statistics

(Statistics ensure that our observations are really reppresentative)

Peer Review study

(Having others look over our sholder helps us make good observations)

Placebo

(Sugar pills help us account for the personal bias factor)

Double blind study

Why do we put so much emphasis on the Scientific Method?

  • Bleeding people with leeches isn’t too healthily.
  • Truth matters.
  • People are so biased that reality is not easily discerned.

Scientist exercise extreme caution before accepting a theory. It took nearly 100 years of experimental evidence before John Dalton’s hypothesis that all matter is composed of small indivisible particles called atoms was universally accepted.

ALCHEMY

Seventeenth century alchemists wanted to turn lead into gold.

Their contribution to chemistry lies in the fact that they did many experiments and keep notes on what they did.

The last part of chapter 1 talks of dual perceptions and associations with chemistry. It is hoped that your experience of learning chemistry may be like the perspective test. That is, sometimes your perception may be that chemistry is challenging while a short time later you attitude may be that chemistry is easy and fun.