Unit 2—States of Matter and Phase Changes
Define all Vocabulary for this unit:
Absolute Zero – Temperature at which all molecular motion stops; 0 Kelvin
Boiling – Phase change from liquid to gas; endothermic
Boiling Point – Point at which evaporation/condensation occur
Celsius – Temperature scale on which water freezes/melts at 0o and evaporates/condenses at
100o
Compound – Atoms from 2 or more elements are chemically combined (ex. H2O, NaCl)
Condensation – Phase change from gas to liquid; exothermic
Element – Pure substance made of only one kind of atom (ex. oxygen, nitrogen)
Evaporation – Phase change from liquid to gas; endothermic
Fahrenheit – Temperature scale on which water freezes/melts at 32 o and
evaporates/condenses at 212o
Freezing – Phase change from liquid to solid; exothermic
Gas – Phase of matter with high kinetic energy, low IMF; particles expand/contract to fit the
size and shape of the container
Heterogeneous – Mixture with different types of particles visible
Homogeneous – Mixture which looks the same throughout
Intermolecular force – Forces that hold molecules of the same substance together
Kelvin – Temperature scale on which 0 = absolute zero
Kinetic Molecular Theory – Combination of laws, hypotheses and facts that describe how
particles move
Liquid – Phase of matter with medium kinetic energy and IMF; maintains volume, but takes
shape of container
Macro view – Can be seen with the naked eye
Matter – Anything that has mass and volume (takes up space)
Melting – Phase change from solid to liquid; endothermic
Melting Point – Temperature at which melting/freezing occurs
Mixture – Physical combination of two or more elements and/or compounds
Particle – A piece of something
Phase Change – Physical change from one state of matter to another (ex. Melting, Evaporating)
Plasma – State of matter where molecules begin to break down; 10,000oC or higher; electrical
Pressure – Measure of how frequently and forcefully molecules hit against the walls of their
container. In a closed container of gas, pressure goes up when temperature goes up, and
pressure goes down when volume goes up
Pure substance – Cannot be physically separated in different types of matter; elements and
compounds
Solid – phase of matter with constant volume and shape; low temperature, high IMF
Solution – Mixture of 2 or more substances, at least one of which is a liquid
Sublimation – Phase changes directly from solid to gas (evaporation) or gas to solid
(condensation)
Temperature – Measure of the average kinetic energy of a substance
Thermal Energy/Heat – Energy which increases the kinetic energy (temperature) of a substance
Thermometer – Instrument used to measure temperature
Complete the following chart to demonstrate your knowledge of the phases of matter…
Phase
Energy
(movement of
particles)
Solid
Vibrate in place
Liquid
Molecules flow
around each
other
Gas
Molecules
break away
from each
other
Plasma
Atoms split
Characteristics
that you see
Tempeture
(medium
and low)
Low
Intermolecular
Force (strong and
weakest)
Strongest
Flows, takes shape
of container,
constant volume
Medium
Medium
Flows, takes shape
of container,
expands/contracts
to fill container
Follows electric
current
High
Weak
highest
Weakest
Holds shape and
volume
Molecular
Diagram
Pg. 240
Complete the table with the words High, Medium, or Low. Each will be used once in each row.
This will show you the relationship between Kinetic Energy and Intermolecular Forces…
Solid
Kinetic Energy of
Particles
Low
Liquid
Medium
Intermolecular Forces
High
Medium
Gas
High
Low
Fill in the blanks and label which chain is Endothermic and which is Exothermic at the top.
Endothermic
Gas
Evaporation
Liquid
Melting
Exothermic
Gas
Condensation
Liquid
Freezing
Solid
Solid
Complete the table to practice your knowledge of phase changes… Hint: Kinetic energy and
Intermolecular forces will either be increasing or decreasing.
Phase Change
Name
Kinetic Energy
Sublimation (E)
Intermolecular
Forces
Decreasing
Increasing
Exothermic or
Endothermic
Endo
Solid → Gas
Solid → Liquid
Melting
Decreasing
Increasing
Endo
Liquid → Gas
Evaporation
Decreasing
Increasing
Endo
Liquid → Solid
Freezing
Increasing
Decreasing
Exo
Gas → Liquid
Condensation
Increasing
Decreasing
Exo
Gas → Solid
Sublimation (C)
Increasing
Decreasing
Exo
On the following graphs: Label states of matter, phase changes, and which is cooling down and
which is heating up.
In the table below draw the micro view (molecule arrangement) for the following substances…
Element
Compound
Mixture
See page 230 of Textbook
See page 230 of Textbook
See page 230 of Textbook
Explain how matter is classified. Use the following terms in your answer: matter, homogenous,
heterogeneous, mixture, pure substance, solution, element, compound.
**See flow chart on page 7 of Kinetic Theory and Phase Change packet**