States, Boiling Point, Melting
Point, and Solubility
Solid
Liquid
Gas
Questions
•
What are the 3 states of matter?
•
Write a definition for each state?
Defining States of Matter
• States of matter are NOT defined by what
they are made of.
– Example: solids can be elements (gold), compounds
(Salt = NaCl), or mixtures (butter)
Element (Au)
Compound (NaCl)
Mixture (Milk, Salt, etc)
Defining States of Matter
• States of matter are defined by whether
they hold SHAPE and VOLUME
Element (Au)
Compound (NaCl)
Mixture (Milk, Salt, etc)
ALL KEEP THE SAME SHAPE AND VOLUME = Solids
Defining States of Matter
• Solids – have a definite SHAPE and
VOLUME.
Element (Au)
Compound (NaCl)
Mixture (Milk, Salt, etc)
ALL KEEP THE SAME SHAPE AND VOLUME
Particle View of a Solid
• Particles in a solid are PACKED
CLOSELY together and they are in a
FIXED POSITION.
Particles vibrate in place
Liquids
• Liquids – has definite VOLUME but no
defined SHAPE
100 ml
Particle View of a Liquid
• Packed CLOSELY (like a solid), but move
FREELY around each other (must stay in
contact).
Gases
• Gases - do NOT have definite SHAPE or
VOLUME.
Bromine gas fills up the entire volume of the container
Particle view of a Gas
• Particles can MOVE FREELY and will
either fill up or squeeze into available
space.
Questions
• 1) Which Statement is True?
– A) Liquids have a definite shape and volume
– B) States of matter are defined by the
substances they are made up of
– C) Gases have a definite shape and volume
– D) Solids have a definite shape and volume
Task
• Draw a diagram of
– A) Gas particles
– B) Liquid particles
– C) Solid particles
Changes in States of Matter
• Thermal Energy – heat energy.
• More thermal energy = More particle movement
Changing States
Increase Thermal Energy (Heat up)
Solid
Liquid
Decrease Thermal Energy (Cool off)
Gas
Melting point
• Melting - change from solid to liquid
• Melting point - SPECIFIC temperature when
melting occurs.
• Each pure substance has a SPECIFIC melting
point.
–
–
–
–
–
Examples:
M.P. of Water = 0°C (32°F)
M.P. of Nitrogen = -209.9 °C (-345.81998 °F)
M.P. of Silver = 961.93 °C (1763.474 °F)
M.P. of Carbon = 3500.0 °C (6332.0 °F)
Melting Point
• Particles of a solid vibrate so fast that they
break free from their fixed positions.
Increasing Thermal Energy
Solid
Liquid
Melting point
Vaporization
• Vaporization – change from liquid to gas
• Vaporization happens when particles in a
liquid gain enough energy to form a gas.
Increasing Thermal Energy
Liquid
Boiling point
Gas
Two Kinds of Vaporization
• Evaporation – vaporization that takes
place only on the surface of the liquid
• Boiling – when a liquid changes to a gas
BELOW its surface as well as above.
Boiling Point
• Boiling Point – temperature at which a
liquid boils
• Each pure substance has a SPECIFIC
boiling point.
– Examples:
– B.P. of Water = 100°C (212°F)
– B.P. of Nitrogen = -195.79 °C (-320.42 °F)
– B.P. of Silver = 2162 °C (3924 °F)
– B.P. of Carbon = 4027 °C (7281 °F)
Boiling Point and Melting Point
WATER – H20
200
Boiling point
Temperature
150
100
Melting point
50
0
-50
-100
-150
time
Solubility
• Maximum amount of a substance that can
be dissolved in a liquid (at a specific
temperature).
Salt (NaCl)
Water (H20)
at 20°C
Solubility
• Solute – substance being dissolved
• Solvent – liquid substance that solute is
dissolved into
Salt (NaCl)
Water (H20)
at 20°C
Solubility
• Solute – ?????? Salt
• Solvent – ????? Water
Salt (NaCl)
Water (H20)
at 20°C
Solubility can change
• Increased Temp = Increased Solubility
• Different substances have different
solubility curves
Solubility of Unknow n Substance at different tem peratures
substance/ml of H20
mg of unknown
3
2.5
2
1.5
1
0.5
0
1
3.8
6.6
9.4
12.2
15
17.8
tem perature (degrees Celcius)
20.6
23.4
26.2