PROPERTIES OF MATTER
CHEMISTRY/PHYSICAL SCIENCE
MINI LESSON 1
 

Vocabulary:
 matter
 density
 solid
 liquid
 gas
 plasma
 physical property
 chemical property
 viscosity
 crystals
 
 
 
 
 
 
 
 
 
 
 
 
 

LAW OF CONSERVATION OF MATTER
Matter cannot be created nor destroyed,
it can only be changed from one form to another.
 
 
 
 
 
 

  matter and energy are interchangeable according to  E=mc2
(E=amount of energy, m= amount of matter, c=constant equal to the velocity of light)

The Law of Conservation of Matter is why we must balance a chemical equation :

C + O2 -------> CO2
(reactants)           (product)

- The total number of atoms in the reactants is equal to the total number of atoms in the product.

- Two pieces of matter cannot occupy the same space at the same time.

    Example: When you get into a bathtub filled with water,
the water level rises (water displacement).
 
 

Matter can be defined as anything that has mass and takes up space (volume).

                   Mass is the amount of MATTER in an object     (mass vs weight)
                  Volume is the amount of space that the MATTER in an object takes up.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Matter can exist in 4 states:
 

1. solid - has definite shape and volume. Example: ice, salt, wood.

2. liquid - has definite volume but no definite shape. Example: water, milk, mercury.

3. gas - has no definite volume or shape. Example: air, water vapor, CO2.

4. plasma - the state of matter that exists at high temperatures, it consists of electrically charged     particles.         Example: sun, nuclear fusion.


 
 
 
 
 
 

Examples of changes of state:
 

1. evaporation - liquid to gas
2. condensation - gas to liquid                     (freezing point = melting point)
3. freezing - liquid to solid
4. sublimation - solid to gas
5. melting - solid to liquid water
Boiling point of water - 100o Celsius
Freezing point of water - 0o Celsius
Relevant vocabulary words:
crystal - arrangement of the particles in a solid in repeating patterns.
viscosity - the property of a liquid that describes how it pours.

 
 
 
 
 
 
 
 
 
 
 

Density - is the mass of a substance per unit of volume or how tightly packed an object's atoms or molecules are.   Less dense materials float on denser materials.  Ice is less dense than water, oil is less dense than water, lead is denser than water, iron is denser than water.  Increasing heat (which is the same thing as increased kinetic energy)  tends to decrease the density of a substance because heating generally causes things to expand, which increases volume, which decreases the mass to volume ratio.  One exception to this general rule is water whose density decreases as it freezes. Density of water (@4oC) =  1 g/cm3
 

Density is a physical property.
Density = mass/volume
Density is expressed in grams per cubic centimeter  (g/cm3)
Example: Find the density of a rectangular object 3cm by 2cm by 1cm, the object has a mass of 12 grams.


              Solution:
                                      V = l x w x h = 3cm x 2cm x 1cm = 6cm3
                                      D = m / V= 12g/6cm3 = 2g/cm3
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

KINETIC THEORY OF MATTER - all matter is made up of tiny particles called molecules, these particles are in constant motion.

                                      SOLID                           LIQUID                               GAS

         000                              0  0  0                          0        0         0
        000                              0  0  0                          0        0         0

- increasing temperature will increase the speed of molecules and result in an increase of kinetic energy.
 
 
 
 
 
 
 
 
 
 
 
 
 
 

PROPERTIES OF MATTER - CHEMICAL AND PHYSICAL

Physical properties - depends only upon matter itself, the identity of the substance does not change. Physical properties can be measured using physical senses.  Examples: color, mass, size, density, magnetic, melting point, boiling point, texture, shape.

Chemical properties - those things that describe the events which occur when two materials react with each other.  Examples: Was heat, light, sound, or some other form of energy generated? Did a reaction take place at all (if not, the materials are non-reactive - which is a chemical property)?  Were gases formed?  Was it endothermic or exothermic?  The chemical properties of an element are determined by the number of valence electrons it has.

Example: a rusting nail

4 Fe +    3 O2    -------->     2 Fe2O3

                                                                                          iron     oxygen                      iron(III) oxide

New substance formed which has its own set of physical and chemical properties,
but,
can be broken back down into the elements which formed it.


























CHANGES IN MATTER - PHYSICAL AND CHEMICAL
 
 

Physical change: change in physical properties - a change in shape, size, or state without a change in actual composition.
- it involves changes in one or more physical properties of a substance but not in the identifying chemical properties of a substance but not in the identifying chemical properties or molecular composition of the substance.
- Example: breaking a rock, melting ice, evaporation, freezing water.

 
Chemical change: Change in which a substance becomes another substance with different properties.

- Example: souring of milk, silver tarnishing, electrolysis of water

- an energy change always accompanies a chemical change - loss or gain of heat, light, or some other form of energy.