| A | B |
|---|
| Precision | a reliable measurement give same results again anf again under same conditins |
| accuracy | indication of how close a measurement is to its accepted value |
| numbers that are always significant | #'s 1-9 |
| When are zeros significant (4) | between digits (509), following digits in a decimal fraction ex: 1.0, .300 , following digits in a whole number with decimal point ex: 100. 1700., line placed above zero |
| percent error | observed value- accepted value over accepted value times 100 = percent error |
| density | d=m/v |
| Energy | capacity to do work or to produce heat |
| kinetic energy | moving energy, forms- thermal, mechanical |
| potential energy | stored energy, energy possessed by objects because of their position or the arrangement of their particles |
| Matter | anything that has mass and volume |
| Joule | unit of energy |
| Element | a substance that cannot be seperated into simpler substances by a chemical change |
| Crystallization | sample of seawater is allowed to evaporate partially, crystals of salt will form |
| plasma | low density, density depends on pressure, expands to fill its container exists only at high temperatures |
| intensive property | doesn't depend on the amount of matter |
| absolute zero | zero point of Kelvin scale, point at which the motion of particles of matter ceases |
| states of matter | solid, liquid, gas, plasma |
| physical property | the characteristics of a substance that can be observed without altering the identity of substance ex: density, color, melting point |
| chemical property | characteristics of a subatnce that cannot be observed without altering the substance ex: Flammability |
| physical change | changes which don't alter the identity of a substance ex: crushing, tearing, and changes in state |
| chemical change | alter the identity of a substance ex: food cooking, burning things |
| distillation | makes use of changes in state from a liquid to a gas to a liquid |
| chromatography | a solution can be seperated by allowing it to flow along a stationary substance |
| Cal/Kilocalorie | 1000 Calories=1kilocalorie |
| Extensive property | a characteristic that depends upon the amount of matter in the sample |
| compound | 2 or more elemetns combined in a chemical reaction |
| mixture | blend of two or more pure substances |
| homogeneous | do not contain visibly different parts ex: seawater, air, |
| heterogeneous | has visibly different parts ex: chocolate chip cookies and granite |
| filteration | seperate heterogenous mixtures, poured through a piece of paper, which lets liquid pass througha nd catches the solid |
| radient energy | energy from the sun |
