Download 2014-2015 KEY TERMS, DEFINITIONS and FORMULAS for

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Key Terms and Definitions for Physical Science, 2014-2015
Chp 1, 13, 14, 11, 12, 2, 8, 9, 3, 4, 5, 6 and 7
Chp 1-1
1. Science – the knowledge obtained by observing natural events and
conditions in order to discover facts and formulate laws or principles that
can be verified or tested. Science is observing, studying and experimenting
to find the nature of things. It is how we discover how things work in the
natural world.
2. Technology – is the application of science for practical uses or purposes.
Advances in science and technology depend on one another.
3. Law – a statement or equation that accurately describes a natural process.
Laws allow predictions to be made about how a system will behave.
4. Theory – is a system of ideas that explains many related observations.
Theories explain WHY something happens and is supported by a wide body
of evidence acquired through scientific investigation.
Chp 1-2
5. Scientific method – a series of steps followed to solve problems including
collecting data, formulating a hypothesis, testing the hypothesis and stating
conclusions. This method helps to organize your thinking about questions.
6. Variable - a factor that changes in an experiment in order to test a
hypothesis. Variables can affect the outcome of an experiment.
7. Mass – a measure of the amount of matter in an object. It is measured in
grams with a triple beam balance.
8. Weight – a measure of the gravitational force exerted on an object. It is
measured in g/cm3 or Newtons (N).
9. Length – a measure of the straight-line distance between two points. Length
is measured in meters with a metric ruler.
10. Volume – a measure of the size of a body or region in three-dimensional
space. Volume tells you how much space an object is taking up. It is
measured with a graduated cylinder in mL or cm3.
Chp 1-3
11. Precision – is the exactness of a measurement. For example 3.1 is less
precise than 3.14159265358979323846264338327950288419716939
12. Accuracy – a description of how close a measurement is to the true value of
the quantity measured. Often in science, multiple trials are done and an
average is taken to improve accuracy.
Page 1 of 11
Chp 13-3
13.
Energy – The capacity to do work
14.
Potential Energy – The energy and object has because of the position,
shape or condition of the object
15.
Kinetic Energy – the energy of an object due to the object’s motion.
16.
Mechanical Energy – the amount of work and object can do because of
the object’s kinetic and potential energies.
Chp 13-4
17.
Law of Conservation of Energy – Energy cannot be created or
destroyed.
Chp 14-1
18.
Temperature – a measure of how hot or cold some is. Specifically, a
measure of the average kinetic energy of the particles in an object.
19.
Thermometer – an instrument that measures and indicates
temperature.
20.
Absolute Zero – the temperature at which molecular energy is at a
minimum. (0 K or -273.16 C)
Chp 14-2
21.
Thermal Conduction – The transfer of energy as heat through a material
22.
Convection – the movement of matter due to differences in density that
are caused by temperature variations.
23.
Convection Current – the vertical movement of air currents due to
temperature variations
Chp 11-1
24. Motion – an object’s change in position relative to a reference point.
25. Frame of reference –Objects that stay in place and are used for comparison
of motion of other objects. The frame of reference objects are treated as if
they are not moving.
26. Displacement – the change in position of an object. It is a measure of the
straight-line distance from a starting point to an ending point.
27. Speed – the distance traveled divided by the time interval during which the
motion occurred.
28. Velocity – the speed of an object in a particular direction.
Chp 11-2
29. Acceleration – the rate at which velocity changes over time; an object
accelerates if its speed, direction or both change.
Page 2 of 11
Chp 11-3
30. Force – an action exerted on an object in order to change the object’s state
of rest or motion. Forces have a magnitude (size) and a direction.
31. Friction – a force that opposes motion between two surfaces that are in
contact.
32. Static friction – the force that resists the initiation of sliding motion
between two surfaces that are in contact and at rest.
33.
Kinetic friction – the force that opposes the movement of two surfaces
that are in contact and are moving over each other.
Chp 12-1
34. Inertia – the tendency of an object to resist a change in motion unless an
outside net force acts on the object.
Chp 12-2
35. Weight – a measure of the gravitational force exerted on an object.
36. Free fall – the motion of a body when only the force of gravity is acting on
the body.
37. Terminal velocity – the constant velocity of a falling object when the force
of air resistance is equal in magnitude (size) and opposite in direction to the
force of gravity.
38. Projectile motion – the curved path that an object follows when thrown,
launched, or otherwise projected near the surface of Earth.
Chp 12-3
39. Momentum – a quantity defined as the product of the mass and velocity of
an object.
Chp 2-1
40.
Matter – anything that has matter and takes up space.
41.
Element – a substance that cannot be broken down or separated into
simpler substances by chemical means.
42. Atom – the smallest unit of an element that maintains the chemical
properties of that element.
43.
Molecule – a group of atoms that are held together by chemical forces. A
molecule is the smallest unit of matter that can exist by itself and retain all
of the substances chemical properties. Molecules are combined in definite
ratios. Example: a molecule of sugar is C6H12O6.
44.
Compound – a substance made up of atoms of two or more different
elements joined by chemical bonds
45.
Pure substance – a sample of matter (either a single element or
compound) that has definite chemical and physical properties.
Page 3 of 11
46.
Mixture – a combination of two or more substances that are not
chemically combined.
Chp 2-2
47.
Melting point – the temperature (and pressure) that a solid becomes a
liquid.
48.
Boiling point – the temperature (and pressure) that a liquid becomes a
gas.
49.
Density – the ratio of the mass of a substance to the volume of the
substance.
50.
Reactivity – the capacity of a substance to combine chemically with
another substance.
Chp 2-3
51.
Physical change – a change of matter from one form to another without
a change in chemical properties.
52.
Chemical change – a change that occurs when one or more substances
change into entirely new substances with different properties.
Chp 8-1
53. Suspension – a mixture in which particles of a material are more or less
evenly dispersed throughout a liquid or gas but settle out when the mixture
is allowed to stand. Solute particles are relatively large and it may be
possible to filter them.
54. Colloid – a mixture consisting of tiny particles that are intermediate in size
between those in solutions and those in suspensions. The tiny particles
remain suspended and cannot be filtered. These particles cause the Tyndall
effect, which scatters light.
55. Emulsion – any mixture of two or more immiscible liquids in which one
liquid is dispersed in the other (using an emulsifier)
56. Solution – a homogeneous mixture throughout which two or more
substances are uniformly dispersed. The very tiny particles dissolve and stay
mixed.
57. Solute – in a solution, the substance that dissolves in the solvent.
58. Solvent – in a solution, the substance in which the solute dissolves.
59. Alloy – a solid or liquid mixture of two or more metals. The properties of the
alloy are a combination of the properties of the 2 or more metals.
Chp 8-2
60. Polar – describes a molecule in which the partial positive and negative
charges are separated. (not as strong as an ionic charge). Caused by
unequal sharing of electrons.
Page 4 of 11
61. Nonpolar – describes a molecule in which the centers of positive and
negative charges are not separated. There is equal sharing of electrons and
these electrons are distributed evenly over the whole molecule.
62. Hydrogen bond – an intermolecular force occurring when a hydrogen atom
that is bonded to a highly electronegative atom of one molecule is attracted
to two unshared electrons of another molecule.
Chp 8-3
63. Solubility – the ability of one substance to dissolve in another at a given
temperature and pressure.
64. Concentration – the amount of a particular substance that is dissolved in a
given volume of solution.
65. Saturated solution – a solution that cannot dissolve any more solute under
the given conditions.
66. Unsaturated solution – a solution that contains less solute than a
saturated solution does and that is able to dissolve additional solute.
67. Supersaturated solution – a solution that holds more dissolved solute than
is required to reach equilibrium. It is highly unstable.
68. Molarity – a concentration unit of a solution expressed in moles of solute
dissolved per liter of solution.
Chp 9-1
69. Acid – any compound that increases the number of hydronium ions (H 3O+)
when dissolved in water.
70. Indicator – a compound that can reversibly change color depending on
conditions such as pH.
71. Electrolyte – a substance that dissolves in water to give a solution that
conducts an electric current.
72. Base – any compound that increases the number of hydroxide ions (OH-)
when dissolved in water.
73. pH - a value that is used to express acidity and basicity (alkalinity) of a
system; each whole number on the scale indicates a tenfold change in
acidity.
Chp 9-2
74. neutralization reaction – the reaction of the ions that characterizes acids
and the ions that characterize bases to form water molecules and a salt.
75. Salt – an ionic compound that forms when a metal atom (or a positive
radical) replaces the hydrogen of an acid. When a salt is soluble in water,
the ions stay separated in solution until the water evaporates.
Page 5 of 11
Chp 3-1
76. Fluid – a nonsolid state of matter (liquid or gas) in which the atoms or
molecules are free to move past one another.
77. Plasma – a 4th state of matter that consists of free-moving ions and
electrons. Plasmas have a variable shape and volume and can conduct
electricity.
78. Energy – the capacity to do work. Energy is the ability to change or move
matter and can take many different forms.
79. Temperature – how hot or cold something is. It is a measure of the average
kinetic energy of the particles in an object.
80. Thermal energy – The total kinetic energy of a substance’s atoms. The more
atoms, the more thermal energy something has.
Chp 3-2
81. Evaporation – the change in state from liquid to gas.
82. Boiling - is evaporation that occurs throughout a liquid at a certain
temperature and pressure.
83. Sublimation – the process of a solid changing directly into a gas (without a
liquid phase).
84. Condensation –the change in state from a gas into a liquid.
85. Melting - change in state from a solid to a liquid.
86. Freezing/solidify – change in state from a liquid to a solid.
Chp 3-4
87. Gas laws – the laws that state the mathematical relationships between
volume, temperature, pressure, and quantity of a gas.
Chp 4-1
88. Electron – a subatomic particle that has a negative charge -1. Located in
energy levels outside of the nucleus.
89. Nucleus – An atom’s central region, which is made up of protons and
neutrons. Almost all of the atom’s mass is in the small, positively-charged,
densely-packed nucleus.
Chp 4-2
90. Proton – a subatomic particle that has a positive charge and that is located
in the nucleus of an atom. Each proton has a charge of +1.
91. Neutron – a subatomic particle that has no charge (0) and that is located in
the nucleus of an atom.
92. Atomic number – the number of protons in the nucleus of an atom.
93. Mass number – the sum of the number of protons and neutrons in the
nucleus of an atom. (always a whole number)
Page 6 of 11
94. Isotope – an atom that has the same number of protons (and same atomic
number) but has a different number of neutrons (and thus a different mass
number).
95. Atomic mass unit – unit of mass for an atom or molecule. Symbol is u. It is
1/12th the mass of a carbon-12 atom.
96. Mole – the SI base unit used to measure the AMOUNT of a substance whose
number of particles is the same as the number of atoms of carbon in exactly
12 g of carbon-12. Specifically, a mole is 6.022 x 1023 particles of anything.
Chp 4-3
97. Orbital – a region in an atom where there is a high probability of finding
electrons.
98. Valence electron – an electron that is found in the outermost energy level of
an atom and that determines the chemical properties of an atom.
99. Photon – a unit or quantum of light. (like a packet of energy)
Chp 5-1
100. Periodic law – the law states that the repeating chemical and physical
properties of elements change periodically with the atomic numbers of the
elements.
101. Period – horizontal row (across) of elements on the periodic table. There
are 7 periods currently.
102. Group – a vertical column (up and down) of elements in the periodic
table. There are 18 groups currently. Elements in a group share chemical
properties.
Chp 5-2
103. Ion – an atom, radical or molecule that has lost or gained one or more
electrons and has a negative or positive charge.
104. Metal – an element that is shiny, conducts (carries) heat and electricity
well. Metals are often malleable (bendable) and ductile (can be pulled into
wires). Mostly solids (2 liquids at room temp)
105. Nonmetal – an element that cannot conduct heat or electricity well. Are
often dull and brittle and can be solids, liquids or gases.
106.
Semiconductor – an element or compound that conducts electric
current better than an insulator does but not as well as a conductor does.
Located on “staircase” on periodic table.
Chp 5-3
107. Alkali metal – elements in group 1. Highly reactive, soft solids.
108. Alkaline earth metal – elements in group 2. Less reactive than group 1,
harder denser and stronger.
Page 7 of 11
109. Transition metal – elements in groups 3-12. Some are less reactive, can
form many cations, fill inner energy levels before outer, most are hard,
dense and have high melting points except for mercury (liquid at room
temp).
110. Halogen – elements in group 17. Most reactive non-metals.
111. Noble gas – elements in group 18. Are non-reactive gasses (inert) that
exist as single atoms not compounds.
Chp 6-1
112. Chemical bond – the attractive force that holds atoms or ions together.
113. Chemical structure – the arrangement of atoms in a substance.
114. Bond length – the average distance between the nuclei of two bonded
atoms.
115. Bond angle – the angle formed by two bonds to the same atom.
Chp 6-2
116. Ionic bond – the attractive force between oppositely charged ions, which
form when electrons are transferred from one atom to another.
117. Covalent bond – a bond that is formed when atoms share one or more
pairs of electrons. Polar covalent bonds do not share electrons equally. Nonpolar covalent bonds do share electrons equally.
118. Metallic bond – a bond formed by the attraction between positively
charged metal ions and the electrons around them.
119. Polyatomic ion – an ion made of two or more atoms.-3
Chp 6-3
120. Empirical formula – the composition of a compound in terms of the
relative numbers and kinds of atoms in the simplest ratio.
121. Molecular formula – a chemical formula that shows the number and
kinds of atoms in a molecule, but not the arrangement of atoms.
Chp 6-4
122. Organic compound – a covalently bonded compound that contains
carbon, excluding carbonates and oxides.
123. Polymer – a large molecule that is formed by more than 5 monomers, or
small units.
124. Carbohydrate – a class of molecules that includes sugars, starches, and
fiber; contains carbon, hydrogen and oxygen.
125. Protein – an organic compound that is made of one or more chains of
amino acids and that is a principal component of all cells.
126. Amino acid – a compound of a class of simple organic compounds that
contain a carboxyl group and an amino acid group and that combine to form
proteins.
Page 8 of 11
Chp 7-1
127. Reactant – a substance or molecule that participates in a chemical
reaction.
128. Product – a substance that forms in a chemical reaction.
129. Chemical energy – the energy released when a chemical compound
reacts to produce new compounds.
130. Endothermic reaction – a chemical reaction that requires energy input.
131. Exothermic reaction – a chemical reaction in which energy is released
to the surroundings as heat.
Chp 7-2
132. Chemical equation – a representation of a chemical reaction that uses
symbols to show the relationship between the reactants and products.
133. Mole ratio – the relative number of moles of the substances required to
produce a given amount of product in a chemical reaction.
Chp 7-3
134. Synthesis reaction – reaction in which two or more substances combine
to form a new compound.
135. Decomposition reaction – a reaction in which a single compound
breaks down to form two or more simpler substances.
136. Combustion reaction – the oxidation reaction of an organic compound,
in which heat is released. Carbon dioxide and water are products.
137. Single-displacement (replacement) reaction – a reaction in which one
element or radical takes the place of another element or radical in a
compound.
138. Double – displacement (replacement) reaction – a reaction in which
two compounds exchange atoms or ions. Products are a precipitate, a gas or
a solid.
139. Oxidation-reduction (redox) reaction – any chemical change in which
one substance is oxidized (loses electrons) and one substance is reduced
(gains electrons).
Chp 7-4
140. Catalyst – A substance that changes the rate of a chemical reaction
without being consumed or changed significantly.
141. Enzyme – a molecule, either protein or DNA, that acts as a catalyst in
biochemical reactions (in living things).
142. Substrate – the reactant in reactions catalyzed by enzymes.
143. Chemical equilibrium – a state of balance in which the rate of a forward
reaction equals the rate of the reverse reaction. The concentration of
products and reactants remains unchanged.
Page 9 of 11
Physical Science Formulas
Chp 13
Gravitational Potential Energy = Mass x Free-Fall Acceleration x Height
grav PE = mgh
Kinetic Energy Equation = ½ x mass x speed squared
KE = ½ mv2
Chp 14
Fahrenheit temperature = (1.8 x Celsius temperature) + 32
TF = 1.8 TC + 32
Celsius temperature = (Fahrenheit temperature – 32) / 1.8
TC = (TF – 32) / 1.8
Kelvin Temperature = Celsius Temperature + 273
TK = TC + 273
Specific Heat Equation:
Energy = specific heat x mass x temperature change
Energy = cm∆T
Chp 11
average speed = distance / time
v = d/t
velocity = distance / time including direction
v = d / t with direction
slope = vertical change / horizontal change
acceleration = (final velocity – initial velocity) / time
a = (VF – Vi) / t
Page 10 of 11
Chp 12
Force = mass x acceleration
f = ma
weight = mass x free fall acceleration
w = mg
momentum = mass x velocity
p = mv
Chp 2
Density = mass / volume
D = m/V
Chp 8
Molarity = moles of solute / liters of solution
M = mol / L
Chp 3
Gas Laws:
Boyle
Increase Pressure = Decrease Volume, with Constant
Temperature
Gay-Lussac Increase Temperature = Increase Pressure, with Constant
Volume
Charles
Increase Temperature = Increase Volume, with Constant
Pressure
Chp 4
Amount (mol) = molar mass / 1 mol = Mass (g)
Mass (g) = 1 mol / molar mass = Amount (mol)
Page 11 of 11