Chapter 1 Flashcards
Chemistry
The central science
The study of matter; its chemical and physical properties, its chemical and physical changes it undergoes - as matter changes, it gains/loses energy.
Matter
Anything that has mass and occupies space.
Energy
The ability to do work and to accomplish some change.
Mass
The measure of the amount of matter.
The Scientific Method
A systematic approach to the discovery of new information.
Characteristics of the scientific method
Observation Formulation of a question Pattern of recognition Developing theories Experimentation Summarizing information
Data
The individual result of a single measurement.
Results
The outcome of an experiment.
Observation
Detectable phenomena about nature.
Observation leads to facts (data).
Facts
Observations about nature that can be reproduced at will, independent of the particular observer (verified by repeated testing).
Inductive reasoning
Specific –> general
Conclude a generality from a limited number of specific examples.
Leads to either scientific law or scientific hypothesis.
Scientific law
A broad statement summarizing a large amount of related facts.
Summarizes large amounts of scientific data and provide descriptions of natural phenomena.
EX: law of gravity, law of conservation of mass/matter, etc.
Many scientific laws can be stated mathematically.
Lack explanatory character. Laws tell you what will happen under a given set of circumstances, but not WHY.
Scientific hypothesis
A speculative explanation of related facts that can lead to the prediction of future behavior.
Testable explanations of observed data. These hypotheses are tested by designing and performing experiments.
Deductive reasoning
General explanation –> prediction of a testable specific result.
Scientific theory
A well-tested and generally accepted hypothesis that explains natural phenomena.
The best current explanation for natural phenomena.
Always tentative and may change as observations of nature accumulate and change.
Scientific model
Used to help illustrate and explain scientific hypotheses, laws, and theories.
Proporties
Characteristics of matter that scientists can use to categorize different types of matter
Ways to categorize matter…
- by state
2. by composition
3 states of matter
- Gas: particles spread widely, no definite shape or volume.
- Liquid: particles close together, definite volume but no definite shape.
- Solid: particles very close together, definite shape and volume.
Pure substance
A substance that has only one component.
Element or compound.
Element
A pure substance that cannot be changed into a simpler form of mater by any chemical reaction.
EX: hydrogen, oxygen
Compound
A pure substance resulting from the combination of two or more elements in a definite, reproducible way, in a fixed ratio.
EX: salt, water
Mixture
A combination of two or more pure substances in which each substance retains its own identity, not undergoing a chemical reaction.
Heterogeneous or homogeneous.
Homogeneous
Uniform composition, particles are well-mixed, thoroughly intermingled.
EX: air, ethanol in water
Heterogeneous
Nonuniform composition, random placement.
EX: oil and water, salt and pepper.
Physical property
Observed without changing the composition or identity of a substance.
Physical change
Produces a recognizable difference in the appearance of a substance without causing any change in its composition or identity.
Conversion from one physical state to another: melting an ice cube.