Foundations of Chemistry: Matter and Measurement

TL;DR

Chemistry is the study of matter and its changes, focusing on its composition, properties, and how it interacts. Accurate measurement is fundamental, requiring correct units, precision, and an understanding of uncertainty. Significant figures and scientific notation help us express measurements honestly and concisely.

1. The Mental Model

Think of chemistry as trying to understand all the "stuff" around you. We want to know what it's made of, what it does, and how we can measure it precisely. It's like being a detective for materials, making sure your tools (measurements) are always reliable.

2. The Core Material

What is Matter?

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Matter is anything that has mass and takes up space (has volume). It's all the "stuff" in the universe.

• Substances: These are pure forms of matter with a uniform and definite composition, like pure water (H₂O) or gold (Au).
  • Elements: Can't be broken down into simpler substances by chemical means (e.g., Oxygen, Iron).
  • Compounds: Formed when two or more elements are chemically combined in a fixed ratio (e.g., Water, Salt).
• Mixtures: Combinations of two or more substances not chemically combined.
  • Homogeneous Mixtures (Solutions): Uniform composition throughout (e.g., salt dissolved in water, air). You can't see the different parts.
  • Heterogeneous Mixtures: Non-uniform composition; you can see distinct parts (e.g., sand and water, salad dressing).

States of Matter

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Matter exists in different physical forms:
* Solid: Definite shape and volume. Particles are t