Chapter 1 “ Introduction to Chemistry”. What is Chemistry?. Chemistry is the study of the composition of “matter” – (matter is anything with mass and occupies space), its composition, properties, and the changes it undergoes.
Chemistry is the study of the composition, structure, and properties of matter and the changes it undergoes – such as burning fuels.
C2H5OH+3O2 2 CO2 + 3 H2O + Energy
Boundaries not firm – they overlap and interact
* Aspirin (C9H8O4) - to relieve pain
* Use of TECHNOLOGY (benefit!)
Let’s examine some information from a graph.
After lead was banned in gasoline and public water supply systems, less lead entered the environment.
1. Observations (uses your senses)
a)quantitative involves numbers = 95oF
b)qualitative is word description = hot
2. Formulating hypotheses (ideas)
- possible explanation for the observation, or “educated” guess
3. Performing experiments (the test)
- gathers new information to help decide
whether the hypothesis is valid
1) Manipulated variable (or independent variable) is the one that we change
2) Responding variable (or dependent variable) is the one observed during the experiment
- A set of well-tested hypotheses that give an overall explanation of some natural phenomenon – not able to be proved
- The same observation applies to many
different systems; summarizes results
- an example would be:
the Law of Conservation of Mass
The procedure that is used to test the hypothesis
Using your senses to obtain information
Hypothesis is a proposed explanation; should be based on previous knowledge; an “educated” guess
Tells what happened
A well-tested explanation for the observations; cannot be proven due to new discoveries
Let’s learn how to ACE these numeric word problems!