VOCABULARY TERMS

1. absolute zero - lowest temperature possible 

2. Avogadro’s number - the number of molecules of any gas present in a volume of 22.41 L

3. chemical symbol - a one or two-letter designation of an element

4. dimensional analysis - the use of a set of units to establish the form of an equation

5. distillation -the action of purifying a liquid by a process of heating and cooling.

6. extensive property - a property that depends on the amount of matter in a sample. (Ex: Mass and volume)

7. heterogeneous mixture - a mixture in which the composition is not uniform throughout the mixture

8. homogeneous mixture - a mixture in which the composition is uniform throughout the mixture

9. intensive property - do not depend on the amount of the substance; (Ex: colour, melting point)

10. Kelvin scale - a unit of measurement for temperature where 0 K is absolute zero 

11. law of conservation of mass - mass is neither created nor destroyed in chemical reactions

12. mole - the amount of a chemical substance that contains as many elementary entities

13. precipitate - the process of transforming a dissolved substance into an insoluble solid from a supersaturated solution. 

14. significant figures- 

All non-zero numbers ARE significant. ...

Zeros between two non-zero digits ARE significant. ...

Leading zeros are NOT significant. ...

Trailing zeros to the right of the decimal ARE significant. ...

Trailing zeros in a whole number with the decimal shown ARE significant.

15. atomic absorption spectrum - detects elements in either liquid or solid samples through the application of characteristic wavelengths of electromagnetic radiation from a light source.

16. atomic emission spectrum -the spectrum of frequencies of electromagnetic radiation emitted due to electrons making a transition from a high energy state to a lower energy state.

17. atomic number - the charge number of an atomic nucleus

18. atomic orbital - a function describing the location and wave-like behavior of an electron in an atom

19. Aufbau principle -in the ground state of an atom or ion, electrons first fill subshells of the lowest available

20. cathode ray - streams of electrons observed in discharge tubes

21. electromagnetic radiation -waves of the electromagnetic field, which propagate through space and carry momentum and electromagnetic radiant energy.

22. electron configuration - the distribution of electrons of an atom or molecule (or other physical structure) in atomic or molecular orbitals.

23. excited state - When an electron temporarily occupies an energy state greater than its ground state

24. ground state - its stationary state of lowest energy

25. Hund's rule - Every orbital in a sublevel is singly occupied before any orbital is doubly

26. isotope - Atoms with the same number of protons but different numbers of neutrons

27. Pauli exclusion principle -no two electrons in the same atom can have identical values for all four of their quantum numbers.

28. photon -minute energy packet of electromagnetic radiation

29. principal energy level - the shell or orbital in which the electron is located relative to the atom's nucleus

30. quantum mechanical model -views electrons within an atom as waves, not as particles as previously believed.

31. Spin -a quantum property of electrons

32. Alloy - a mixture of chemical elements of which at least one is a metal.

33. Anion - a negatively charged ion

34. atomic radius -a measure of the size of its atom

35. Brittle - hard but liable to break or shatter easily.

36. Cation- a positively charged ion

37. chemical formula - the elements in a compound and the relative proportions of those elements

38. Ductile - able to be deformed without losing toughness

39. electron dot structure - diagrams that describe the chemical bonding between atoms in a molecule

40. Electronegativity - a measure of an atom's ability to attract shared electrons to itself

41. Ion -  an atom or group of atoms that has an electric charge

42. ionic bond - linkage formed from the electrostatic attraction between oppositely charged ions in a chemical compound

43. ionic compound - compounds made up of ions that form charged particles when an atom

44. ionic radius - the radius of a monatomic ion in an ionic crystal structure

45. ionization energy - the amount of energy required to remove an electron from an isolated atom or molecule.

46. metallic bond - a force that holds atoms together in a metallic substance. 

47. polyatomic ion - a group of covalently bonded atoms that carries a net charge due to the fact that the total number of electrons in the molecule is not equal to the total number of protons in the molecule.

48. representative element - Elements in which all the inner shells are complete but the outer shell is incomplete

49. sea of valence electrons - surrounds the positively charged atomic nuclei of the interacting metal ions.

50. valence electron -the electrons in the outermost shell, or energy level, of an atom

51. covalent bond - A covalent bond is a chemical bond that involves the sharing of electrons to form electron pairs between atoms.

52. coordinate covalent bond - a covalent bond (a shared pair of electrons) in which both electrons come from the same atom.

53. dipole interaction - A bond or molecule whose ends have opposite charges

54. dispersion force - a temporary attractive force that results when the electrons in two adjacent atoms occupy positions that make the atoms form temporary dipoles.

55. Nonpolar - molecules that do not have any electrical charges or partial charges

56. polar bond -  a covalent bond between two atoms where the electrons forming the bond are unequally distributed.

57. polar molecules - molecules that have a dipole or an uneven distribution of charge across their geometry resulting in one side being positive and the other side negative.

58. VSEPR - a model used to predict 3-D molecular geometry based on the number of valence shell electron bond pairs among the atoms in a molecule or ion.

59. representative particle - the smallest unit in which a substance naturally exists

60. empirical formula- a chemical formula showing the simplest ratio of elements in a compound rather than the total number of atoms in the molecule.

61. molecular formula - the exact number of different types of atoms present in a molecule of a compound.

62. skeleton equation - equations with simply the chemical formulas of the products and reactants, no mention of state, and no atom balancing on either side of the equation

63. Catalyst - a substance that increases the rate of a chemical reaction without itself undergoing any permanent chemical change.

64. combination reaction- a reaction in which two reactants combine to form one product.

65. decomposition reaction -a chemical reaction in which one reactant breaks down into two or more products.

66. single-replacement reaction - a reaction in which one element is substituted for another element in a compound.

67. activity series - a list of elements in decreasing order of their reactivity.

68. double-replacement reaction - a type of reaction where part of of one reactant is replaced by part of another reactant.

69. combustion reaction - a chemical reaction between substances, usually including oxygen and usually accompanied by the generation of heat

70. oxidation-reduction (redox) reaction - a type of chemical reaction that involves a transfer of electrons between two species.

71. spectator ion - The ions which do not participate in chemical reactions and present the same on both sides of the reactions

72. Stoichiometry - the determination of the proportions in which elements or compounds react with one another. 

73. limiting reagent -the reactant that gets consumed first in a chemical reaction and therefore limits how much product can be formed.

74. excess reagent -reactants that are not used up when the reaction is finished

75. surface tension - what allows objects with a higher density than water to float on a water surface

76. Solvent - the liquid in which a solute is dissolved to form a solution.

77. Solute - the minor component in a solution, dissolved in the solvent.

78. sphere of hydration -The charged particles will form hydrogen bonds with a surrounding layer of water molecules. 

79. Hydrate - a compound, typically a crystalline one, in which water molecules are chemically bound to another compound or an element.

80. Molarity- a unit of concentration expressed as the number of moles of dissolved solute per liter of solution.

81. Anhydrous - (of a substance, especially a crystalline compound) containing no water.

82. Thermochemistry -the study of the heat energy that is associated with chemical reactions and/or phase changes such as melting and boiling.

83. Enthalpy - the measurement of energy in a thermodynamic system. 

84. Endothermic - (of a reaction or process) accompanied by or requiring the absorption of heat.

85. Exothermic - (of a reaction or process) accompanied by the release of heat.

86. specific heat capacity - the quantity of heat (J) absorbed per unit mass (kg) of the material when its temperature increases 1 K (or 1 °C)

87. Calorimetry- used to measure the amount of thermal energy transferred in a chemical or physical process.

88. heat of fusion -the quantity of heat necessary to change 1 g of a solid to a liquid with no temperature change

89. heat of solidification -  the heat liberated by a unit mass of liquid at its freezing point as it solidifies: equal to the heat of fusion.

90. heat of vaporization -the amount of heat needed to turn 1 g of a liquid into a vapor, without a rise in the temperature of the liquid.

91. the heat of condensation -heat evolved when a vapor changes to a liquid 

92. enthalpy (heat) of the solution - the change in enthalpy that results when one mole of solute (component 1) is dissolved in a solvent (component 2).

93. collision theory -the rate of a chemical reaction is proportional to the number of collisions between reactant molecules.

94. activation energy -the minimum energy required to cause a process (such as a chemical reaction) to occur.

95. activated complex- a collection of intermediate structures in a chemical reaction when bonds are breaking and forming. 

96. reversible reaction -a chemical reaction in which the reactants react to form the products and simultaneously the products again form the reactants.

97. equilibrium constant - the value of its reaction quotient at chemical equilibrium

98. le Châtelier's principle -if a dynamic equilibrium is disturbed by changing the conditions, the position of equilibrium shifts to counteract the change to reestablish equilibrium.

99. Gibb's Free Energy - the amount of energy available to do work.

100. Entropy -the degree of disorder or uncertainty in a system