Chemistry - Middle School

You'll be in your element when you review these terms related to chemistry. Learn about chemical reactions, atoms and molecules, phases of matter, and much more. This list is just the catalyst you need to improve your chemistry vocabulary.
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Full list of words from this list:

words only definitions & notes
  1. absolute temperature
    temperature measured on the absolute scale
  2. absorption
    a process in which one substance permeates another
  3. accuracy
    the quality of being near to the true value
  4. acid
    a sour water-soluble compound with a pH of less than 7
  5. activation energy
    the energy that an atomic system must acquire before a process (such as an emission or reaction) can occur
  6. addition reaction
    a chemical reaction in which one molecule is added to another
  7. alcohol
    a volatile compound made by distillation
  8. alkaline
    relating to or containing an alkali
  9. allotrope
    a structurally different form of an element
  10. alloy
    a mixture containing two or more metallic elements
  11. amorphous
    without real or apparent crystalline form
  12. anion
    a particle with a negative electric charge
  13. aqueous solution
    a solution in water
  14. atom
    the smallest component of an element
  15. atomic mass
    the property of an atom that causes it to have weight
  16. atomic number
    quantity of protons in the nucleus of an atom of an element
  17. atomic weight
    (chemistry) the mass of an atom of a chemical element expressed in atomic mass units
  18. balance
    bring into equilibrium
  19. base
    a compound reacting with an acid to form a salt and water
  20. beaker
    a flatbottomed jar made of glass or plastic
  21. binary compound
    chemical compound composed of only two elements
  22. boil
    bring to the temperature at which a liquid changes to vapor
  23. boiling point
    the temperature at which a liquid boils at sea level
  24. Boyle's law
    the pressure of an ideal gas at constant temperature varies inversely with the volume
  25. brittle
    having little elasticity
  26. buffer
    (chemistry) an ionic compound that resists changes in its pH
  27. bunsen burner
    a gas burner used in laboratories
  28. buoyancy
    the tendency to float in water or other liquid
  29. catalyst
    substance that initiates or accelerates a chemical reaction
  30. cation
    a particle with a positive electric charge
  31. chain reaction
    a series of chemical reactions in which the product of one is a reactant in the next
  32. charge
    the quantity of unbalanced electricity in a body
  33. Charles's law
    (physics) the density of an ideal gas at constant pressure varies inversely with the temperature
  34. chemical bond
    an electrical force linking atoms
  35. chemical change
    process determined by substances' composition and structure
  36. chemical energy
    that part of the energy in a substance that can be released by a chemical reaction
  37. chemical formula
    a representation of a substance using symbols for its constituent elements
  38. chemical property
    a property used to characterize materials in reactions that change their identity
  39. chemical reaction
    a process in which substances are changed into others
  40. chemistry
    the science of matter
  41. chromatography
    a process used for separating mixtures by virtue of differences in absorbency
  42. coefficient
    a constant number that serves as a measure of some property
  43. cohesion
    the force that holds together molecules in a solid or liquid
  44. colloid
    a mixture with properties between those of a solution and fine suspension
  45. combustion
    a reaction of a substance with oxygen to give heat and light
  46. composition
    the way in which someone or something is put together
  47. compound
    a substance formed by chemical union of two or more elements
  48. concentration
    the strength of a solution
  49. condensation
    process of changing from a gas to a liquid or solid state
  50. conductivity
    the property of transmitting heat, electricity, or sound
  51. conductor
    a substance that readily serves as a medium for transmission
  52. covalent bond
    a chemical bond that involves sharing a pair of electrons between atoms in a molecule
  53. crucible
    a vessel used for high temperature chemical reactions
  54. crystal
    a solid having a highly regular atomic structure
  55. crystalline
    consisting of or containing or of the nature of crystals
  56. decomposition reaction
    (chemistry) separation of a substance into two or more substances that may differ from each other and from the original substance
  57. density
    the amount per unit size
  58. deposition
    the natural process of laying something down
  59. desalination
    the removal of salt
  60. diatomic
    of or relating to a molecule made up of two atoms
  61. dilution
    a solution reduced in strength or concentration
  62. dissolve
    pass into a solution
  63. distillation
    purifying a liquid by boiling it and condensing its vapors
  64. Dmitri Mendeleev
    Russian chemist who developed a periodic table of the chemical elements and predicted the discovery of several new elements (1834-1907)
  65. ductile
    capable of being shaped or bent or drawn out
  66. electron
    an elementary particle with negative charge
  67. element
    a substance that cannot be separated into simpler substances
  68. endothermic
    occurring or formed with absorption of heat
  69. endothermic reaction
    a chemical reaction accompanied by the absorption of heat
  70. energy
    any source of usable power
  71. enzyme
    a complex protein produced by cells that acts as a catalyst
  72. equilibrium
    a chemical reaction and its reverse proceed at equal rates
  73. evaporation
    the process of becoming a suspension of particles in the air
  74. exothermic
    occurring or formed with the release of heat
  75. exothermic reaction
    a chemical reaction accompanied by the evolution of heat
  76. family
    a collection of things that are similar in some way
  77. first law of thermodynamics
    the fundamental principle of physics that the total energy of an isolated system is constant despite internal changes
  78. freezing
    the withdrawal of heat to change something from a liquid to a solid
  79. freezing point
    the temperature below which a liquid turns into a solid
  80. gas
    state of matter distinguished from solid and liquid states
  81. heat
    a form of energy transferred by a difference in temperature
  82. heterogeneous
    consisting of elements not of the same kind or nature
  83. homogeneous
    all of the same or similar kind or nature
  84. immiscible
    (chemistry, physics) incapable of mixing
  85. indicator
    a substance that changes color to show something's presence
  86. inorganic compound
    any compound that does not contain carbon
  87. ion
    a particle that is electrically charged positive or negative
  88. ionic
    containing or involving electrically charged particles
  89. ionic bond
    a chemical bond between oppositely charged ions
  90. isotope
    atom with same atomic number, different number of neutrons
  91. kinetic theory
    (physics) a theory that gases consist of small particles in random motion
  92. law of conservation of matter
    a fundamental principle of classical physics that matter cannot be created or destroyed in an isolated system
  93. law of definite proportions
    (chemistry) law stating that every pure substance always contains the same elements combined in the same proportions by weight
  94. liquid
    fluid matter having no fixed shape but a fixed volume
  95. litmus test
    a method of determining if a solution is acidic or basic
  96. luster
    the property of something that shines with reflected light
  97. malleable
    capable of being shaped or bent
  98. mass
    the property of a body that causes it to have weight
  99. mass number
    the sum of the number of neutrons and protons in an atomic nucleus
  100. matter
    that which has mass and occupies space
  101. melting point
    the temperature at which a solid turns into a liquid
  102. meniscus
    the curved upper surface of a liquid in a vertical tube
  103. metal
    a chemical element or alloy that is usually a shiny solid
  104. metallic bond
    a chemical bond in which electrons are shared over many nuclei and electronic conduction occurs
  105. metalloid
    a nonmetallic element that has some of the properties of metal
  106. miscible
    capable of being mixed, in chemistry
  107. mixture
    a substance consisting of substances blended together
  108. mole
    the molecular mass of a substance expressed in grams
  109. molecule
    the simplest structural unit of an element or compound
  110. neutral
    having only a limited ability to react chemically
  111. neutron
    a subatomic particle with zero charge
  112. nucleus
    the positively charged dense center of an atom
  113. orbit
    the path of an electron around the nucleus of an atom
  114. orbital
    relating to the path of one body around another
  115. osmosis
    diffusion of molecules through a semipermeable membrane
  116. oxidation
    the process by which a substance combines with oxygen
  117. oxidize
    enter into a combination with oxygen
  118. periodic law
    (chemistry) the principle that chemical properties of the elements are periodic functions of their atomic numbers
  119. periodic table
    arrangement of chemical elements according to atomic number
  120. pH
    a measure of the acidity or alkalinity of a solution
  121. phase
    a distinct state of matter in a system
  122. phase change
    a change from one state (solid or liquid or gas) to another without a change in chemical composition
  123. pH scale
    a measure of the acidity or alkalinity of a solution
  124. physical change
    a change from one state (solid or liquid or gas) to another without a change in chemical composition
  125. physical property
    any property used to characterize matter and energy and their interactions
  126. plasma
    a fourth state of matter distinct from solid, liquid or gas
  127. precipitate
    a substance separated from a solution or suspension
  128. precision
    the quality of being exact
  129. product
    a chemical substance formed as a result of a reaction
  130. property
    a basic or essential attribute shared by members of a class
  131. proton
    a stable particle with positive charge
  132. reactant
    a substance that is altered during a chemical process
  133. reaction
    a process in which a substance is changed into another
  134. reagent
    a substance for use in chemical reactions
  135. rusting
    the formation of reddish-brown ferric oxides on iron by low-temperature oxidation in the presence of water
  136. salinity
    the relative proportion of salt in a solution
  137. solid
    matter with definite shape at room temperature and pressure
  138. solubility
    the quality of being easily dissolved in liquid
  139. solute
    the dissolved matter in a homogenous liquid mixture
  140. solution
    a homogeneous mixture of two or more substances
  141. solvent
    a liquid substance capable of dissolving other substances
  142. state of matter
    (chemistry) the three traditional states of matter are solids (fixed shape and volume) and liquids (fixed volume and shaped by the container) and gases (filling the container)
  143. subatomic particle
    a body having finite mass and internal structure but negligible dimensions
  144. sublimation
    a change directly from the solid to the gaseous state
  145. subscript
    character printed slightly below and to the side of another
  146. substance
    a particular kind of matter with uniform properties
  147. surface tension
    phenomenon at a liquid's surface from intermolecular forces
  148. suspension
    a mixture in which fine particles are supported by buoyancy
  149. temperature
    the degree of hotness or coldness of a body or environment
  150. test tube
    glass tube closed at one end
  151. thermodynamics
    physics concerned with heat and other forms of energy
  152. valence
    the capacity of something or someone to react with or affect others
  153. valence electron
    an electron in the outer shell of an atom which can combine with other atoms to form molecules
  154. vaporization
    the process of becoming a suspension of particles in the air
  155. viscosity
    resistance of a liquid to flowing
  156. volume
    the amount of 3-dimensional space occupied by an object
  157. weight
    the vertical force exerted by a mass as a result of gravity
  158. yield
    an amount of a product
Created on Sun Feb 26 20:29:41 EST 2017 (updated Wed Apr 19 16:39:05 EDT 2017)

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