By: Ali Maredia
Edit 9/11/12: More information has been added!
In modern chemistry, there are four main people who made valuable advancements in this field.
- Antoine Lavosier, “Father of Modern Chemistry”:
Lavosier experimented with combustion, disapproved the Theory of Phlogiston, called Priestly’s gas oxygen, and helped develop the metric system.
- John Dalton:
Dalton proposed the Atomic Theory.
- Fredrich Kekule, “Father of Organic Chemistry”:
Kekule showed how carbon atoms unite.
- Dmitri Mendeleev:
Mendeleev arranged elements in a chart known today as the Periodic Table of Elements.
- Marie Curie:
Curie discovered the two radioactive elements, radium and polonium.
The Scientific Method:
The scientific Method incorporates observations, hypotheses, and experiments. There are four main steps:
- Observation: record facts about natural phenomenon.
There are two types of observation: quantitative and qualitative. Quantitative uses numbers, while qualitative does not use numbers and is more detailed.
- Hypotheses: tentative and testable statements capable of being supported by observational evidence.
- Experiments: controlled observations that test hypotheses (control is used as a standard for comparison). This step guides for rejection or refinement of the hypothesis.
- Theory or Scientific Law:
A theory is a model that is well established, well tested, and highly reliable explanations of hypotheses, but may be subject to change as new areas of science are being developed. They explain why things happen. A scientific law must be a concise statement that summarizes results of a broad variety of observations in experiments. They do not explain why things happen.
The Three Main States of Matter(excluding plasma):
- Solid: definite shape and volume-particles are tightly packed, therefore incompressible (cannot be pressed into smaller volume ). Solids will expand slightly when heated.
- Liquids: definite volume but will take shape of its container, particles are less closely packed than solids, but still are incompressible-liquids will expand when heated also.
- Gases: no definite shape and no definite volume-large amounts of space between particles, therefore easily compressed. To measure gas, you must study temperature and pressure.
The Difference Between Gas and Vapor:
- Vapor is a gaseous state of a substance that is solid or liquid in room temperature.
- Gas is a substance that is naturally in a gaseous state in room temperature.
Physical and Chemical Properties: