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Chapter 1
Matter and Measurements
| Question | Answer |
|---|---|
| A systematic approach to research | Scientific Method |
| A tentative explanation for a set of observations | Hypothesis |
| A concise statement of a relationship between phenomena that is always the same under the same conditions | Law |
| A unifying principle that explains a body of facts and/or those laws that are based on them | Theory |
| Anything that occupies space and has mass | Matter |
| A form of matter that has a difinite composition and distinct properties | Substance |
| Composition of the mixture is the same throughout | Homogenous Mixture |
| Composition is not uniform throughout | Heterogeneous |
| Means can be used to separate a mixture into its pure components | Physical |
| A substance that cannot be separated into simpler substancesby chemical means | Element |
| A substance composed of atoms of two or more elements chemically united in fixed proportions | Compound |
| Does not alter the composition or idnetity of a substance | Physical change |
| alters the composition or identity of the substance involved | Chemical change |
| Depends on how much matter is being considered | Extensive property |
| Does not depend on how much matter is being considered | Intensive property |
| Mass/Volume | Density |
| how close a measureent is to the true value | Accuracy |
| how close a set of measurements are to each other | precision |
| all the digits in a measurement that are known with certainty plus a last digit that must be estimated | significant figures |
| Matter is neither created nor destroyed | Law of Conservation of Mass |
| A given compound always contains the same relative numbers and kinds of atoms | Law of Constant Composition |
| Different ratioes of the numbers and kinds of atoms give rise to different compounds | Law of Multiple Proportions |
| Measured mass/charge of electrons | Thompson |
| Measured mass of electron | Millikan's Experiment |
| Protons have opposite charge of electrons | Rutherford's E. |
| determined atomic # | Moseley |
| electrons pass from the cathode to the anode | cathode ray tube |
| determined the magnitude of the electric charge of the electron | Millikan |
| Measured the charge to mass ratio e/m | Thomson |
| developed the nuclear model of the atom | Rutherford |
| Established that protons are not evenly distributed throughout an atom | Gold Foil E. |
| Neutrons | Chadwick |
| compounds that have a certain number of water molecules attached to them | hydrates |