Chem 1

Introduction to Chemistry

Chemistry is the study of matter, its properties, composition, and behavior.
It is often called the central science because it connects physical sciences with life sciences and applied sciences.

Atoms are the smallest units of elements.
Each atom consists of three main types of subatomic particles:
- Protons: Positively charged (+) particles found in the nucleus.
- Neutrons: Uncharged particles also located in the nucleus.
- Electrons: Negatively charged (–) particles that orbit the nucleus.

Elements: Pure substances that cannot be broken down further by chemical means.
- Examples include oxygen (O), carbon (C), and nitrogen (N).
Compounds: Substances formed when two or more elements chemically bond together.
- They can be ionic (electron transfer) or covalent (electron sharing).

Water (H2O) is vital for all known forms of life and has unique properties due to its molecular structure:
- Cohesion: Water molecules stick together, providing surface tension.
- Adhesion: Water molecules can also stick to other substances.
- High Heat Capacity: Water can absorb a lot of heat without a significant temperature change, helping regulate temperature.
- Density Anomaly: Ice floats because it is less dense than liquid water, allowing it to insulate aquatic environments.

Chemical reactions involve the transformation of substances through breaking and forming bonds:
- Reactants: Substances that undergo change.
- Products: New substances formed as a result of the reaction.
Types of reactions include synthesis, decomposition, and exchange reactions.

Understanding the principles of chemistry is fundamental for exploring complex systems in both biology and the environment.