Unit 1: Review Flashcards
Define a “Hypothesis”
A hypothesis is a tentative explanation
Define a “Law”
A law summarizes related observations, but does not explain them
What are the 3 steps of scientific method?
Observation ➡️ Hypothesis ➡️ Test
Define a “Theory”
Explains parts of the universe, makes predictions about how it will react under given circumstances, hypothesis that have held up under rigorous testing
What must a theory be?
A theory must be falsifiable; it must be possible to prove it wrong
(ie: good “energies” emitted make people feel nice: there is no way to potentially disprove this because “energies” is not a measurable quantity)
1000 trials proving a theory true
And 1 trial proving the theory false
Is the theory proven or disproved?
Disproved, a single trail proving the theory false, makes the theory disproved.
What 3 things make a theory more or less credible?
Whether it makes small or risky predictions, whether few or many trials to disprove it have been conducted, and whether they are locally or more widely applicable, all respectively
Define Matter
Matter is anything with mass and volume
Define Composition
Composition describes what the matter is made up of
Define a “Substance”
Matter with a defined composition
Define a “Mixture”
A substance who’s composition can be physically separated
Define a “Pure Substance”
A substance who’s composition can’t be separated by physical means
Define Homogenous
A mixture that is the same throughout
Define Heterogenous
A mixture that is not the same through out
Define a “Compound”
A pure substance who’s components can be chemically separated
Define an “Element”
A pure substance who’s components can’t be chemically seperated
What are the 4 main points of Dalton’s Atomic Theory?
- All matter is made out of atoms that are indestructible, hard, indivisible spheres
- All atoms of a given mass are identical in mass and property
- Compounds are formed by two or more different kinds of atoms
- Chemical reaction is a rearrangement of atoms
Define “Chemistry”
The study of properties and transformations of matter, and the interaction of matter and energy
Define “Science”
Science is the systematic organization of knowledge in the form of testable explanations and predictions about the universe
Define a “Property”
Something about a substance that can be felt with the 5 senses or measured with an instrument
Define a “Physical property”
A property that can be perceived by our 5 senses or by an extension of our senses (instruments) without any chemical manipulation of the substance
Define a “Chemical property”
Something which can be perceived by our 5 senses or an extension of them (instruments) only after chemical manipulation
Give an example of a physical property
Density etc.
Give an example of a chemical property
Toxicity or acidity etc.
