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Ch.1-3 vocab
vocab
Term | Definition |
---|---|
Temperature | measurement of kinetic energy of atoms or molecules(degrees) |
Absolute Zero | when all motion of atoms stop |
Accuracy | how close a measured value is to the accepted value or target |
Precision | how close a series of measurements |
Percent Error | ratio of error to the accepted value |
Percent Error(formula) | % error= [(experimental-accepted)/excepted]x100 |
Matter | takes up space and has mass |
Weight | measurement of matter and gravity (pounds) |
Scientific Method(order) | 1. observation 2. hypothesis 3. experiment 4. theory 5. law |
Observation | use of the senses |
Quantitative | numeric |
Qualitative | qualities |
Hypothesis | testable prediction/statement |
Experiment | used to test a hypothesis |
Independent Value | what you change |
Dependent Value | changes in response to independent value |
Controlled Variable | standard in he experiment |
Theory | describes why things happen |
Law | describes how/what things happen, a fact of nature |
Base Units | defined unit of measurement that's based on an object or event in the physical world |
Derived Units | combination of base units |
Scientific Notation | convenient way of writing very small or large #s |
Density | measure of how packed an object is |
Density(formula) | D=M/V |
Substance | matter that has a uniform unchanging composition |
Element | substance that cannot be separated into simpler substance |
Compound | combination of 2+ elements, chemically combined |
Mixture | combination of substances |
Heterogeneous | not uniform mixture |
Homogeneous | uniform mixture, constant composition |
Physical Properties | characteristics that can be observed or measured w/out changing the sample's composition |
Intensive Properties | independent of the amount of substance presnt |
Chemical Properties | ability of a substance to combine w/or change into 1+ substances |
Flamability | ability to burn |
Reactivity | how easily a substance combines chemically with other substances |
Solid | Particles- close, orderly Shape- fixed Volume- fixed |
Liquid | Particles- loose, random Shape- changes Volume- fixed |
Gas | Particles- fast, random, spaced out Shape- changes Volume- Changes |
Plasma | ionized gas w/enough energy to have free electrons |
Physical Changes | altering a substance w/out changing its composition |
Chemical Changes | process where 1+ substance changes into a new substance |
Evidence of a chemical reaction? | -gas produced -color change -change in smell -light produced -temp change |
Law of Conservation of Mass | mass is neither created nor destroyed |
Filtration | separation based on particle size |
Distillation | separation based on boiling points |
Crystallization | formation of solid particles from a solution |
Chromatography | separation based on particle size |