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phsyical science
classification of matter
Question | Answer |
---|---|
matter | anything that has mass and takes up space. |
atom | particles that make up matter. |
element | sample of matter of which all of the atoms are alike (oxygen) |
compound | material made from two or more elements that are combined (h2o) |
substance | can be either an element or a compound |
mixture | material made up of two or more substances (kool aid) |
heterogeneous mixture | materials can be easliy distinguished (different candies) |
homogeneous mixture | two or more substances are uniformly spread out (brownie mix, or salt water) |
solution | another name for homogeneous mixture |
colloid | heterogeneous mixture that never settles. (milk or gelatin) |
suspension | heterogeneous mixture containing a liquid in which visible particles never settle. (muddy water) |
tyndall effect | scattering of light by particles in a mixture (smog) |
smog | form of air pollution, is a type of mixture that results from auto exhaust, burning things, CFC's, etc. |
physical property | any characteristic of a material that you can observe without changing the substances that make up the material... shape, color, size, density, boiling point(melting point), state of matter(5 senses) |
physical change | change in size, shape, or state of matter (or any physical property)... boiling, evaporating, subliming, freezing. |
chemical property | characteristics of a substance that indicates if it can undergo a certain chemical change... fammability, combustibility, volatility. |
chemical change | a change of one substance in a material to a different substance... Burning, rusting, many different chemical reactions. |
law of conservation of mass | matter (mass) is neither created nor destroyed during a chemical change. |
solid | state of matter with a definite volume and a definite shape. |
liquid | state of matter with a definite volume, but no definite shape. |
gas | state of matter with no definite volume and no definite shape. |
plasma | gas-like mixture of positively and negatively charged particles. |
thermal expansion | almost all matter expands as it gets hotter, and contracts as it gets cooler. |
evaporation | liquid changes to a gas at temperatures below the boiling point. |
sublimation | solid changes directly to a gas without going to a liquid state. |
boiling | liquid changes to as gas at or above the boiling point. |
condensation | gas changes to liquid |
heat of fusion | amount of energy needed to change a material from a solid state to the liquid state... for water... it is 334Kj/Kg... so it takes 334Kj of energy. |
boyle's law | if you decrease the volume of a container of gas, the pressure of the gas will increase, assuming that the temperature does not change... rubber balloon. |
charles law | if you increase the temperature of a gas, the volume of that gas will increase, assuming that pressure stays the same. balloon |
buoyancy | the ability of a fluid, liquid or gas, to exert an upward force on an object immersed in it. |
archimedes' principle | the buoyancy force on an object in a fluid is equal to the weight of a fluid displaced by the object. |
pascal's principle | pressure applied to a fluid is transmitted unchanged throughout the fluid... squeezing a balloon. |
heat of vaporization | the amount of energy that it takes to change a material from a liquid to a gas. |
crystals | particles with repeating geometric shapes. |
pressure(P) | the amount of force exerted per unit of area, and it is measured in pascal's (Pa) |
melting | changing from a solid to a liquid. |
freezing | changing a liquid to a soild |
kinetic-molecular theory | says that there is a temperature where all molecular motion increases, this is called absolute zero and it happens at -273.15 degrees C. |
Gay-Lussac's Law | states that the pressure of a sample of gas at constant volume, is directly proportional to its temperature in Kelvin. |
bernoulli's principle | as the velocity of a fluid increases, the pressure exerted by the fluid decreases. |
differance between physical properties, chemical properties, physical changes, and chemical changes. | physical property-observe without changing. physical change-change size, shape, or state of matter. chemical property-substance can undergo chemical change. chemical change-change from one substance to another substance. |
describe the law of conservation of energy and how it applies to chemistry or physical science. | states that energy may neither be created nor destroyed. Therefore the sum of all the energies in the system is a constant. |
tell the difference between a homogeneous and heterogeneous, give examples. | homogeneous is when two or more substances are uniformly spread out. like milk, and salt water. heterogeneous is when it can be easily distinguished, like mixed candy. |
describe a solid, liquid and gas. (shape, volume, molecular arrangement, and molecular motion.) | solid- holds shape and has a fixed volume. liquid- shape of container, free surface and fixed volume. gas- shape to container and volume to container. |
explain what thermal expansions is and how it works. give examples. | almost all matter expands as it gets hotter, and contracts as it gets cooler. example: like a crowd at a concert , as it gets warmer, people get restless and push and spread out, as it gets cooler, people huddle from warmth again. |
identify changes of state, | solid is definite volume and shape. liquid is definite volume but no definite shape. gas is no definit shape nor volume. |
discuss how pressure works, know pascal's law. | amount of force exerted per unit of area. pascal's law is pressure applied to a fluid. like squeezing a balloon. |
understand how buoyancy works, know archimedes prinicple; how it affects boats. | if the buoyancy force and weight is equal then the boat will float. archimedes is when the buoyancy has equal weight and force. |
bernouilli's principle and how it works to keep a airplance in the air. | when the velocity of the fluid increases, the pressure exerted by the fluid decreases. it results to the plance being able to stay in the air. |