Question | Answer |
Matter | anything that has mass and takes up space (macro/microscopic) |
Chemistry | the study of matter and the changes it undergoes |
Mass | describes the quantity of matter in an object |
Weight | the force of gravity exerted on an object- can be different on different planets, use the word weighing though we really mean massing |
Law of Conservation of Mass | in a non-nuclear chemical reaction, mass is not creatd or destroyed |
Solid | keeps shape and volume, low compressability |
Liquid | keep volume but not shape, relative compressability |
Gas | doesn't hold shape or volume, high compressability |
Physical Changes | invlove altering the physical state of a substance without changing its chemical composition (melting, freezing, boiling, condensation) |
Physical Properties | describes the color, odor, melting/freezing point, density, etc. of a substance and do not change the composition or identity of a substance |
Chemical Changes | involve altering chemical identity of a substance ( also called chemical reaction) |
Chemical Properties | characteristics of how a substances undergoes chemical change- such as: hydrogen burns in oxygen to make water |
Pure Substance | a single chemical entity- one kind of matter with a set of constant physical and chemical properties- may be element or a compound- it cannot be seperated into other kinds of matter by any physical properties |
Element | contain single type of atom- they cannot be decomposed by any chemical reaction into simpler substances |
Atom | the smallest piece possible of an element |
Elemental Symbols | abbreviation used to represent an atom of a element- one or two letters, only first one is capitalized |
Compound | substance composed of two or more elements chemically combined |
Law of Definite Proportions | different samples of the same compound always contain its constituent elements in the same proportion by mass- i.e. all samples of CO2 have the same ratio by mass of C to O |
Mixture | contain two or more substances each or which retain it own distinct identity and can be seperated by physical means |
Heterogeneous Mixture | mixture has distinct phases or parts- i.e. oil and water, sand in water, iron fillings in salt |
Homogeneous Mixture | mixture has a uniform appearance and composition thoughout |
Precision | refers to the closeness of the set of values obtained from identical measurements of a quantity (values close together) |
Accuracy | refers to the closeness of a single measurement to its true value (close to true value) |
Significant Figures | number of meaningful digits in a repeated number, only the last digit in the number is not known with certainty |
Doubtful Digit | the last digit is uncertain but signficant- ex. when you measure a rod you get 9.12, 9.11, and 9.13; the first two numbers (9.1) are certain, the next digit is an estimate with some uncertainty |
Scientific Notation | used to remove ambiguity of a number- especially to simplify very large/small numbers |
Exact Numbers | have infinite number of significant figures (counted quantities, definitions)- ex. there are 9 coins in a bottle, 12 inches in a foot |
Density | how concentrated some form of matter is- specifically the ratio of mass to volume |
Meter | SI base unit of length |
Kilogram | SI base unit of mass |
Second | SI base unit of time |
Derived Unit | combinations of the fundalmetal quantities of length, mass, time, etc.- ex. density in g/mL, velocity in m/s |
Temperature | scale established by arbitrarily, but consistantly, setting fixed points and temperature increments called degrees |
Factor-label/Dimensional Analysis Method | used to convert one unit to another |
Unit/Conversion Factors | used to perform factor-label calculations- ex. 7 days in a week, 10 pennies to a dime |