Chemisty Final

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Chemisty Final
2012-12-18 22:18:42

Chemistry Vocab words for semester 1 final
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  1. Reactants
    a substance or molecule that participates in a chemical reaction
  2. Products
    a substance that forms in a chemical reaction
  3. Matter
    anything that has mass and takes up space
  4. Density
    the ratio of the mass of a substance to the volume of the substance; often expressed as grams per cubic centimeter ofr solids and liquids and as grams per liter for gases
  5. Element
    a substance that cannot be separated or broken down into simpler substances by chemical means; all atoms of an element have the same atomic number
  6. Molecule
    the smallest unit of a substance that keeps all of the physical and chemical properties of that substance; it can consist of one atom or two or more atoms bonded together
  7. Compound
    a substance made up of atoms of two or more different elements joined by chemical bonds
  8. Mixture
    a combination of two or more substances that are not chemically combined
  9. Homogeneous Mixture
    describes something that has a uniform structure or composition throughout
  10. Heterogeneous Mixture
    composed of dissimilar components
  11. Endothermic
    describes a process in which heat is absorbed from the enviroment
  12. Exothermic
    describes a process in which a system releases heat into the environment
  13. Heat
    the energy transferred between objects that are at different temperatures; energy is always transferred from higher temperature objects to lower temperature objects until thermal equilibrium is reached
  14. Temperature
    a measure of how hot something is; specifically a measure of the average kinetic energy of the particles in an object
  15. Specific Heat
    the quantity of heat required to raise a unit of mass of homogeneous material 1 K or 1* C in a specified way given constant pressure and volume
  16. Hypothesis
    a theory or explanation that is based on obersvations and that can be tested
  17. Theory
    an explanation for some phenomenon that is based on observation, experimentation, and reasoning
  18. Law of Conservation of Mass
    the law that states that mass cannot be created or destroyed in ordinary chemical and physical changes
  19. Accuracy
    a description of how close a measurement is to the true value of the quantity measured
  20. Precision
    the exactness of a measurement
  21. Electron
    a subatomic particle that has a negative electric charge
  22. Nucleus
    an atom's central region, which is made up of protons and neutrons
  23. Proton
    a subatomic particle that has a positive charge and that is found in the nucleus of an atom; the number of protons of the nucleus is the atomic number, which determines the identity of an element
  24. Neutron
    a subatomic particle that has no charge and that is found in the nucleus of an atom
  25. Atomic Number
    the number of protons in the nucleus of an atom; the atomic number is the same for all atoms of an element
  26. Mass Number
    the sum of the numbers of protons and neutrons of the nucleus of an atom
  27. Isotopes
    an atom that has the same number of protons (atomic number) as other atoms of the same element but has a different number of neutrons (atomic mass)
  28. Orbital
    a region in an atom where there is a high probability of finding electrons
  29. Electromagnetic spectrum
    all of the frequencies or wavelengths of electromagnetic radiation
  30. Quantum Numbers
    a number that specifies the properties of electrons
  31. Atomic Mass Unit
    a special mass unit that shows the mass of one atom (amu)
  32. Mole
    the SI base unit used to measue the amount of substance whose number of particles is the same as the number of atoms in 12 g of carbon-12
  33. Molar Mass
    the mass in grams of 1 mol of a substance
  34. Avogadro's number
    6.022 x 10^23, the number of atoms or molecules in 1 mol
  35. Valence Electron
    an electron that is found in the outermost shell of an atom and that determines that atom's chemical properties
  36. Group
    a vertical column of elements in the periodic table; elements in a group share chemical properties
  37. Period
    a horizontal row of elements in the periodic table
  38. Alkali Metals
    one of the elements of Group 1 of the periodic table
  39. Alkaline Earth Metals
    one of the elements of Group 2 of the periodic table
  40. Halogen
    one of the elements of Group 17 of the periodic table; halogens combine with most metals to form salts
  41. Noble Gas
    an unreactive element of Group 18 of th periodic table that has eight electrons in its outer level
  42. Transition Metal
    one of the metals that can use the inner shell before using the outer shell to bond
  43. Alloy
    a solid or liquid mixture of two or more metals
  44. Ionization Energy
    the energy required to remove an elecron from an atom or ion
  45. Electron Shielding
    the reduction of the attractive force between a positively charged nucleus and its outermost electrons due to the cancellation of some of the positive charge by the negative charges of the inner electrons
  46. Electronegativity
    a measure of the ability of an atom in a chemical compound to attract electrons
  47. Energy
    the capacity to do work
  48. Atom
    the smallest unit of an element that maintains the properties of that element