Card Set Information

2012-01-17 06:06:07
chemistry ch1 vocab

vocabulary words ch 1
Show Answers:

  1. accuracy
    How closely a measured value agrees with the correct value
  2. atom
    • the smallest particle of an element that maintains it chemical identity through all chemical and physical changes.
    • The basic unit of an element that can enter into chemical combination.
  3. atomic number
    the number of protons in the nucleus of an atom.
  4. chemical change
    a change in which one or more new substances are formed
  5. compound
    a substance composed of two or more elements in fixed proportions.
  6. density
    mass per unit volume
  7. element
    a substance that cannot be decomposed into simpler substances by chemical means.
  8. endothermic
    describes a process that absorbs heat energy
  9. heat
    a form of energy that flows between two samples of matter because of their difference in temperature
  10. energy
    the capacity to do work or transfer heat
  11. exothermic
    describes processes that release heat energy.
  12. heterogeneous mixture
    a mixture that does not have uniform composition and properties throughout.

    Ex: sand with metal files in it.
  13. homogeneous mixture
    a mixture that has uniform composition and properties throughout
  14. kinetic energy
    • energy that matter possesses by virtue of it motion.
    • energy expended by a moving object or energy of motion
  15. mass
    a measure of the amount of matter in an object.
  16. matter
    anything that has mass and occupies space.
  17. mixture
    a sample of matter composed of variable amounts of two or more substances, each of which retains its identity and properties.
  18. molecule
    the smallest particle of an element or compound that can have a stable independent existence.
  19. physical change
    • a change in which in substance changes from one physical state to another, but no substances with different compositions are formed.
    • ex: water>ice>vapor
  20. potential energy
    energy that matter possesses by virtue of its position, condition, or composition
  21. precision
    how closely repeated measurements of the same quantity agree with one another.
  22. properties
    characteristics that describe samples of matter.
  23. substance
    any kind of matter all specimens of which have the same chemical composition and physical properties
  24. symbol
    a letter or group of letters that represents an element
  25. temperature
    a measure of the intensity of heat, that is, the hotness or coldness of a sample or object
  26. Gas matter
    molecules are separated by distances that are large compared with the size of the molecule
  27. liquid matter
    Molecules in a liquid are close together but are not held so rigidly in position and can move past one another
  28. solid matter
    molecules held close together in an orderly fashion with little freedom of motion
  29. Diatomic molecules
    • Contains only two atoms.
    • Ex: H-Hydrogen, O-Oxygen, N-nitrogen, F-fluorine, I-iodine, Br-bromine, Cl-chlorine
  30. Mass Number (A)
    Is the total number of neutrons and protons present in the nucleus of an atom of an element.
  31. Atomic number (Z)
    Is the number of protons in the nucleus of each atom of an element.
  32. Neutrons
    Electrically neutral particles having a mass slightly greater than that of protons
  33. Protons
    The positively charged particles in the nucleus
  34. Electrons
    Negatively charged particles
  35. Law of conservation of Mass
    Is that matter can be neither created nor destroyed.
  36. chemistry
    The science that describes matter-its properties, the changes it undergoes, and the energy that accompany those processes.