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Pre-Chemistry 1
8th Grade Earth Science
Question | Answer |
---|---|
What is a Proton? | a positively charged particle that determines the identity of the atom, or it's element. Found in the nucleus. Affects element |
What is a Neutron? | a particle with no charge (neutral). Found in nucleus. Affects mass. |
What is an Electron? | Tiny, negatively charged particles that move rapidly in the electron cloud outside of the nucleus. Affects charge. |
Atomic Number | The number of protons in a single atom. Also number of electrons in a single atom. Top number |
Mass Number | The total amount of protons AND neutrons in an element's nucleus. Mass Number - Atomic Number = Amount of Neutrons. Used to identify different isotopes of a particular element. |
Atomic Mass | This number is a calculated average of an elemental atom's mass. Bottom number |
List the examples of Physical Properties, define Physical Properties | -Characteristics that can be observed without changing the composition of the substance. Color, Phase/State, Size/Shape/Volume,Viscosity, Freezing/Melting Point, Boiling/Condensation Point, Mass, Density |
List the examples of Physical Changes, define Physical Change | -A change in the form or appearance of a sample of matter, but does NOT change its composition. Changing from a solid, to a liquid, to a gas, or to a plasma (or the reverse), Change in shape or size, A substance dissolving into another substance. |
List the examples of Chemical Properties, define Chemical Properties | -A characteristic that can only be determined by changing the chemical identity of a substance. Flammability (catches on fire), Combustibility (explosive), Luminescence (produces light), Oxidation (rusting) Level of Reactivity |
List the signs of Chemical Changes, define Chemical Change | -A change in the composition of a substance – a chemical reaction. Changes color, Gives off a gas/odor, Heat is produced, Heat is absorbed, A solid is produced |
Solids | -has definite shape & volume. -atoms are tightly packed together & vibrate in place. -lowest amount of energy |
Liquids | -has definite volume, but doesn’t have shape. -atoms move more freely – ability to flow. |
Gas | -doesn’t have definite volume or shape. -atoms have freedom of movement – fill in available spaces. |
Plasma | -state of electrically charged free-moving particles. -most common phase of matter in stars -have greatest amount of energy. |
Definition of Thermal Energy | The total kinetic (moving) energy of all the particles in a sample of matter. |
Melting Point | The temperature where matter changes from a solid into a liquid. Water’s melting point is 0oC or 273 K. |
Freezing Point | The temperature where matter changes from a liquid into a solid. Water’s freezing point is 0oC or 273 K. |
Condensation Point | The temperature where matter changes from a gas into a liquid. Water’s melting point is 100oC or 373 K |
Boiling (Vaporization)Point | The temperature where matter changes from a liquid into a gas. Water’s boiling point is 100oC or 373 K |
Sublimation | Process that occurs when a solid turns into a gas (skips liquid). This happens with liquid Nitrogen, dry ice, and comets. |
Deposition | Process that occurs when a gas turns into a solid (skips liquid). This is how frost forms. |