Vocab Term | Definition |
Pure Substance | any element or compound, a substance is the same throughout and has a fixed chemical composition |
Mixture | two or more substances mixed together without being chemically combined. The substances can be separated without a chemical reaction. |
Physical Properties | a substance's color, odor, density, melting point and boiling point, ductility, and conductivity |
Chemical Properties | the ability of a substance to react with other substances |
Periodic Table | a chart of elements arranged by their atomic number (the number of protons in their nucleus) |
Periods | rows that begin with atoms containing one valence electron and end with atoms with a complete outer shell containing 8 electrons |
Groups | members have similar chemical and physical properties |
Solids | atoms, ions, and molecules are locked into fixed positions, giving the substance a fixed volume and shape |
Liquids | when energy is transferred to a substance, its particles start to move around melting the solid, this has volume, but no fixed shape |
Gases | if more heat is applied to a liquid, its particles will move more rapidly, breaking all connections and turn into this |
Acid | a special type of compound that forms hydrogen ions when dissolved in water, they taste tart or sour |
Base | a special type of compound that forms hydroxide ions in water, they taste bitter and are slippery |
Acid/Base Reactions | combine to produce a water and a salt |
Displacement | a change in an object's position |
Distance | the total length moved by the object |
Velocity | the rate and direction an object moves |
Acceleration | the change in an object's velocity (measured m/s/s) |
Momentum | mass multiplied by velocity |
Friction | a force from rubbing surfaces that opposes motion |
First Law of Motion | also called the Law of Inertia- an object at rest stays at rest, and an object in motion stays in motion at the same velocity unless an unbalanced force acts upon it |
Second Law of Motion | the net force acting on a body equals its mass times acceleration |
Third Law of Motion | for every action, there is an equal and opposite reaction |
Energy | the ability to do work |
Kinetic Energy | the energy of motion |
Potential Energy | stored energy |
Law of Conservation of Energy | energy can change its form, but its total quantity is always conserved |
Thermal Energy | a form of kinetic energy, basedon the vibrations and movements of atoms and molecules |
Temperature | a measure of the average kinetic energy of an object's particles; the higher the temperature, the greater their movement |
Heat | a transfer of energy from an object with a higher temperature to one with a lower temperature |
Nuclear Fission | splitting of nuclei of large atoms, releasing nuclear energy |
Nuclear Fusion | the joining together of nuclei of small atoms- hydrogen into helium- also releasing nuclear energy |
Chain Reaction | when a nucleus splits, its extra neutrons split other nuclei, releasing more energy and nuclei, splitting even more nuclei |
Nuclear Reactions OR Conservation of Mass and Energy | in nuclear reactions, small amounts of matter are converted into large amounts of energy |
Mechanical Waves | seismic, water, or sound passing through a medium; particles of medium pass along the energy of the wave |
Electromagnetic Radiation | can pass through some forms of matter but do not require it; can pass through a vacuum or outer space; includes invisible waves as well as visible light |
Refraction | a wave bends when passing through a different medium |
Reflection | waves bouncing back |
Diffraction | waves bending around |