Chem Terms
Terms
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- Property
- Any characteristic that allows one to recognize a particular type of matter and to distinguish it from other types
- Element
- 100 basic substances that make up all matter. Cannot be decomposed into simpler substances
- Atoms
- The building blocks of matter. Each element has a specific type of atom
- Molecules
- two or more atoms joined together in specific shapes
- Gas
- State of matter that has no fixed shape and conformes to the container
- Liquid
- distinct volume, no specific shape
- Solid
- Both definite shape and volume
- Pure Substance/Substance
- Matter that has distinct properties and a composition that doesn't vary from sample to sample
- Compounds
- Substances composed of two or more elements
- Mixtures
- combinations of two or more substances in which each substances retains its own chemical identity.
- Diatomic
- Existing naturally with two atoms ex. O2
- Law of constant composition/law of definite proportions
- The observation that the elemental composition of a pure compound is always the same
- Physical Properties
- Can be measured without changing the identity and composition of a substance. Color, odor, density, melting point, boiling point, and hardness.
- Chemical Properties
- Describe the ways a substance may change (react) to form other substances. ex. flammability.
- Intensive properties
- Ones that do not depend on the amount such as temp, MP, and density
- Extensive properties
- Depend on the amount of the sample, with two examples being mass and volume.
- Physical changes
- a substance changes appearance, but not composition. ex. all changes in state
- Chemical changes/chemical reactions
- a substance is formed into a chemically different substance. ex. combustion
- Distillation
- Boiling off a liquid to separate it
- Chromatography
- "the writing of colors"
- Scientific Method
- Guidelines for the practice of science. obs, pattern, form & test hypo, theory
- Hypothesis
- Tentative explanation
- Scientific Law
- concise verbal statement or a mathematical equation that summarizes a broad variety of observations and experiences
- Theory
- an explanation of the general causes of certain phenomena, with considerable evidence or facts to support it.