States, Boiling Point, Melting Point, and Solubility

Solid GasLiquid

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

Solid GasLiquid

Increase Thermal Energy (Heat up)

Decrease Thermal Energy (Cool off)

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.

Solid Liquid

Increasing Thermal Energy

Melting point

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

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

Melting point

Boiling point

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 – ??????

• Solvent – ?????

Salt (NaCl) Water (H20) at 20°C

SaltWater

Solubility can change

• Increased Temp = Increased Solubility

• Different substances have different solubility curves

Solubility of Unknown 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)

mg

of

un

kn

ow

n

su

bsta

nce/ m

l o

f H

20