1. States, Boiling Point, Melting
Point, and Solubility
Solid GasLiquid

2. Questions
• What are the 3 states of matter?
• Write a definition for each state?

3. 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)

4. 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

5. 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

6. Particle View of a Solid
• Particles in a solid are PACKED
CLOSELY together and they are in a
FIXED POSITION.
Particles vibrate in place

7. Liquids
• Liquids – has definite VOLUME but no
defined SHAPE
100 ml

8. Particle View of a Liquid
• Packed CLOSELY (like a solid), but move
FREELY around each other (must stay in
contact).

9. Gases
• Gases - do NOT have definite SHAPE or
VOLUME.
Bromine gas fills up the entire volume of the container

10. Particle view of a Gas
• Particles can MOVE FREELY and will
either fill up or squeeze into available
space.

11. 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

12. Task
• Draw a diagram of
– A) Gas particles
– B) Liquid particles
– C) Solid particles

13. Changes in States of Matter
• Thermal Energy – heat energy.
• More thermal energy = More particle movement

14. Changing States
Solid GasLiquid
Increase Thermal Energy (Heat up)
Decrease Thermal Energy (Cool off)

15. 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)

16. Melting Point
• Particles of a solid vibrate so fast that they
break free from their fixed positions.
Solid Liquid
Increasing Thermal Energy
Melting point

17. Vaporization
• Vaporization – change from liquid to gas
• Vaporization happens when particles in a
liquid gain enough energy to form a gas.
GasLiquid
Increasing Thermal Energy
Boiling point

18. 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.

19. 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)

20. Boiling Point and Melting Point
Melting point
Boiling point

21. Solubility
• Maximum amount of a substance that can
be dissolved in a liquid (at a specific
temperature).
Salt (NaCl) Water (H20)
at 20°C

22. Solubility
• Solute – substance being dissolved
• Solvent – liquid substance that solute is
dissolved into
Salt (NaCl) Water (H20)
at 20°C

23. Solubility
• Solute – ??????
• Solvent – ?????
Salt (NaCl) Water (H20)
at 20°C
Salt
Water

24. Solubility can change
• Increased Temp = Increased Solubility
• Different substances have different
solubility curves
Solubility of Unknow n Substance at different temperatures
0
0.5
1
1.5
2
2.5
3
1 3.8 6.6 9.4 12.2 15 17.8 20.6 23.4 26.2
temperature (degrees Celcius)
mgofunknown
substance/mlofH20