Science Terms

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Science Terms

• TAKS Objective 4

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def Compound

• Composed of atoms of different substances that
  are chemically combined

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def Element

• A substance that can not be broken down into
  simpler substances

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def Mixture

• Combination of substances that do not combine
  chemically but do retain their individual
  properties

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def Physical properties

• Characteristic of a material that can be observed
  without changing the identity of the material

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def Buoyancy

• Ability of a fluid to exert and upward force on
  an object immersed in the fluid

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def Density

• A ratio that compares the mass of an object to
  its volume

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def Viscosity

• A measure of the resistance of a liquid to flow.

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def Law of conservation of mass

• State that mass is neither created nor destroyed

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def Balanced chemical equation

• Reaction in which the number of atoms of each
  kind of element is equal of both sides

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def Physical change

• Alters the properties of a substance, but not its
  chemical composition

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def Rock cycle

• Continuous dynamic set of processes by which
  rocks are changed into other types of rock

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def Igneous rock

• Rock formed from magma hardening (physical
  change)

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def Sedimentary rock

• Rock formed from rock fragments being compacted
  (physical change)

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def Metamorphic rock

• Rock formed when heat and pressure are applied to
  other rocks, these new rocks have new chemical
  composition (chemical change)

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def State of matter

• Physical forms in which all matter naturally
  exists

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def Chemical change

• Process involving one or more substances changing
  into new substances

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def Digestion

• The process of making food absorbable by breaking
  it down into simpler chemical compounds

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def Periodic group

• A column of elements on the periodic table, these
  elements will have similar properties

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def Alkali metals

• Elements in group 1A, very reactive, contain one
  valence electron

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def Noble Gases

• Elements in group 8A, are not reactive, contain 8
  valence electrons

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def Halogens

• Elements in group 7A, very reactive, contain 7
  valence electrons

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def Oxidation

• The loss of electrons from the atoms of a
  substance

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def Rusting

• The oxidation of iron

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def Solubility

• The maximum amount of solute that will dissolve
  in a given amount of solvent at a specific
  temperature and pressure

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def Solute

• The substance that dissolves

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def Solution

• Uniform mixture that may contain solids, liquids,
  or gases

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def Solvent

• The dissolving medium

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def Universal solvent

• Water- due to its polarity and ability to
  dissolve many different solutes

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def Polar

• Description of covalent solid in which electrons
  are shared unequally given the molecule charged
  parts

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def Acid

• A substance that tastes sour, reacts with metals
  and turns blue litmus paper red

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def Base

• A substance that tastes bitter, feels slippery,
  and turns red litmus paper blue

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def Condensation

• The process by which gas such as water vapor
  changes to liquid such as water- how clouds are
  formed

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def Precipitation

• Forms of water such as rain, snow, sleet, or hail
  that fall from clouds and reach the earths
  surface

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def Evaporation

• The process by which molecules at the surface of
  a liquid absorb enough energy to change to the
  gaseous state, such as water vapor