Science Vocab

• Acid


  Ph of less than 7
• Atom


  Smallest particle in a chemical element or compound that has the chemical properties of that element.
• Base


  Ph of more than 7
• Catalyst


  Substance that increases the rate of a chemical reaction
• Chemical change


  Result in the formation of one or more new substances with new chemical and physical properties
• Chemical Formula


  Constructed from the symbols of the elements composing the substance
• Chemical Properties


  Be recognized only when substances react or do not react chemically with one another, that is, when they undergo a change in composition
• Chemical Symbol


  One or two letter abbreviation derived from the elements name.
• Compound


  Pure substance that are composed of two or more types of elements that are chemically combined.
• Conductivity


  The ability of a material to conduct electricity or heat
• Electrons


  A negatively charged subatomic particle found outside of the nucleus of the atom
• Element


  Simplest form of a pure substance that cannot be broken into anything else by physical or chemical means.
• Heterogenous Mixture


  Is not uniform throughout, the component substances can be visibly distinguished.
• Homogenous Mixture

  Is uniform throughout, the substances are evenly mixed and cannot be visibly distinguished.
• Law of Conservation of Mass


  The amount of matter does not change during a chemical reaction, only the atoms are rearranged to form new substances. No matter can be created or destroyed through chemical or physical means.
• Metal

  Elements with similar properties found on the left side of the "staircase" on the periodic table.
• Metalloid


  Elements with similar properties that create a "staircase" on the periodic table.
• Mixture


  Physical combinations of two or more different substances that retain their own individual properties and are mixed together.
• Neutrons

  A subatomic particle with no charge (neutral) found in the nucleus of the atom.
• Nonmetal

  Elements with similar properties found on the right side of the "staircase" on the periodic table.
• Periodic table

  A quick reference for associating the name and symbol of an element.
• pH


  Scale used to classify solutions
• Physical change

  Do not change the composition of a substance, only the physical properties.
• Physical properties


  Can be observed and measured without changing the kind of matter studied.
• Precipitate


  A solid substance formed when two solutions are chemically combined.
• Products


  New substances formed in a chemical reaction and are located on the right side of the arrow in a chemical equation.
• Protons

  A positive subatomic particle found in the nucleus of an atom.
• Reactants


  Substances broken apart or combined in a chemical reaction and are located on the left side of the arrow in a chemical equation.
• Reactivity


  The tendency of a substance to undergo chemical changes.
• Solubility


  Ability to dissolve in a liquid.
• Adhesion


  When the atoms or molecules of a substance stick to other substances.
• Cohesion


  When the atoms or molecules of a substance stick together.
• Condensation


  When a gas transforms into a liquid as a result of cooling.
• Density


  Mass per unit volume: the amount of matter in a given amount of space.
• Evaporation


  When a liquid transforms into a gas as a result of heating.
• Heat of Vaporization


  The amount of heat that must be absorbed if a certain quantity of liquid is vaporized at a constant temperature.
• Hydrosphere


  All of the waters on Earth's surface.
• Polarity


  Having a positive and negative end (pole) (i.e. Water is a polar molecule because it has a negatively charged side-the oxygen atom-and a positively charged side-the two hydrogen atoms.)
• Precipitation


  rain, snow, sleet, or hail that falls to the ground.
• Salinity


  A measure of the amount of salt in a body of water.