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33 Cards in this Set
- Front
- Back
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Physical Changes |
A change in which the matter's physical appearance is altered, but composition remains unchanged i.e. a change in the state of matter.
Examples: ice melting, cutting a piece of paper, heat an iron bar until it glows hot. |
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Chemical Changes |
A change in which one or more kinds of matter are transformed to new kinds of matter with altered compositions i.e. chemical reactions.
Examples: milk turns sour, combustion, combining vinegar & baking soda, photosynthesis. |
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States of Matter |
Solid: retains a fixed volume & shape, does not flow, particles are tightly packed
Liquid: assumes the shape of the container it occupies, flows easily, particles are close together with no particular arrangement
Gas: assumes the shape & volume of its container, move freely, particles are separated |
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Endothermic Reaction |
The reaction requires heat i.e. the system absorbs heat from its surroundings. |
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Exothermic Reaction |
The reaction produces heat i.e. the system releases heat into its surroundings. |
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Phase Change Diagram |
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Melting |
Physical change from a solid to a liquid. During this phase change, temperature does NOT change as all the inputted heat energy is contributing to the phase change. |
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Freezing |
Physical change from a liquid to a solid. (Opposite of melting). During this phase change temperature does NOT change as all the heat energy released is contributing to the phase change. |
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Evaporation |
Physical change from a liquid to a gas. During this phase change temperature does NOT change as all the heat energy inputted is contributing to the phase change (similar to melting, the molecules are moving from a semi-free arrangement in a liquid to a very free arrangement in a gas. Because heat energy excites molecules, they become more spaced apart.) |
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Condensation |
Physical change from a gas to a liquid. During this phase change temperature does NOT change as all the heat energy released is contributing to the phase change (similar to freezing, the molecules are releasing heat and therefore going from a more disorganized arrangement to a more packed arrangement. Heat excites molecules and by releasing heat, the particles will become more ordered and move around less.) |
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Sublimation |
A substance goes directly from a solid to a gas without passing through a liquid phase. This occurs in very unique temperature and pressure environments. |
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Deposition |
This is the opposite of sublimation. A substance goes directly from a gas to a solid. This occurs in very unique temperature and pressure environments. An example of this is in sub-freezing air water vapor changes directly to ice like snow in clouds. |
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Atoms |
The smallest amount of an element. Two or more atoms can be joined together to form a molecule (i.e. H2). |
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Elements |
A basic substance that cannot be simplified i.e. oxygen, helium, etc... |
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Protons |
Positively charged subatomic particles that reside in an atom's nucleus. |
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Neutrons |
Neutral charged subatomic particles that reside in an atom's nucleus. |
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Electrons |
Negatively charged subatomic particles that orbit an atom's nucleus. |
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Democritus |
He hypothesized that all matter is composed of tiny, indestructible units called atoms. They move about in space to combine and form macroscopic objects. |
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John Dalton |
Dalton's Atomic Theory: 1) elements are composed of atoms 2) atoms of a given element are the same size, mass and other properties 3) atoms cannot be subdivided, created or destroyed 4) atoms of different elements combine to form chemical compounds 5) in chemical reactions, atoms are combined, separated or rearranged |
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JJ Thomas |
He was awarded the Nobel Prize for his discovery of the electron. He proposed the "plum pudding model" of the atom that said the atom was composed of electrons surrounded by a "soup" of positive charge to balance the electron negative charge. |
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Ernest Rutherford |
The "father of nuclear physics". He pioneered the Rutherford model of the atom that stated there is a large concentration of charge in a very small central volume of the atom (this region also contributes to the bulk of the atomic mass). This region would be named the "nucleus" in later years. |
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Neils Bohr |
Developed the Bohr model of the atom. He proposed that electrons revolve in orbits around the atomic nucleus. |
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Periodic Table |
Chemical elements are arranged on the basis of their atomic number, electron configuration and chemical properties. |
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Atomic Symbol |
A code for a chemical element. It is usually derived from the name of the element i.e. "He" for Helium. |
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Atomic Number |
The number of protons found in the atom's nucleus. |
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Atomic Mass |
The atomic mass is the mass of the atom. It is usually made up of the weight of the protons and neutrons found in the nucleus. The electron mass does not contribute much at all. |
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Groups and Families |
A group (also called a family) is a column of elements on a periodic table. The elements in a group will have the same number of electrons in their outermost shell. |
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Periods |
A period is a row of elements on a periodic table. |
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Alkali Metals |
Found in Group 1 of the periodic table. These are very reactive metals and are malleable, ductile and good conductors of heat and electricity. |
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Alkaline Earth Metals |
Found in Group 2 of the periodic table. These are somewhat reactive. They are silver colored and soft. |
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Transition Metals |
The 38 elements of Group 3 through Group 12 on the periodic table. As with all metals, they are ductile, malleable and conduct electricity and heat. These elements have complex electron orbiting behavior. |
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Halogens |
Group 17 of the periodic table consisting of Fluorine (F), Chlorine (Cl), Bromine (Br), (Iodine), and Astatine ( At). |
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Noble Gases |
Group 18 of the periodic table consisting of odorless, colorless, monoatomic (one atom) gases with very low reactivity. |
