Book K, Chemical Building Blocks
Chapter 1, An Introduction to Matter
Section 1 -- Describing matter (see "Discover" p. 14)
Matter is :
-anything that has mass and takes up space
Properties of matter:
hardness, texture, shape, temperature, flammability, size, color,
melting point, boiling point, state (phase)
Characteristic properties of matter (things that do NOT change no
matter what the sample of a substance is like):
- color
- odor
- phase (state) at room temperature
-melting (freezing) point
- boiling point
- density
-solubility
- heat and electrical conductivity
-hardness
Changes in matter:
- physical changes:
- alter the form of a substance but do not change its identity
examples: -freezing
-melting
- condensation
- boiling
- evaporation
- tearing
- crushing
- chemical changes
- a substance changes into a new substance
examples: -burning of wood
- cooking of an egg
- rusting of iron
- souring of milk
Types of matter:
1. mixtures
- two or more substances that are mixed but
not chemically combined.
- physical combinations of materials that can be separated by physical means.
examples: seasoning mix, chocolate milk
Types of mixtures:
a.) homogeneous mixture
-- evenly mixed
-- salt and water
b.) heterogeneous mixture
-- unevenly mixed
-- sand, iron, water, and marbles
2. pure substances:
a.) elements
- cannot be changed into simpler substances
- about 92 naturally occurring elements
- examples:
iron, aluminum, oxygen
Click here to see a web site with pictures of many elements
b.) compounds
- formed from the chemical combination of two or more elements
- examples:
oxygen and hydrogen combine to form water
Section 2, Measuring Matter
Mass
- a measure of the amount of matter in a substance
- measured in kilograms in the SI system
1 kilogram (kg) = 1000 grams (g)
practice measureing mass here
- Mass is not really the same as weight. Weight is a measure of the
pull of gravity on an object. Weight
changes if gravity changes. Where would you weigh less?
moon, Venus, Mercury, Mars, Pluto
Volume
- the amount of space matter occupies
- can be calculated several ways
1. measuring a regular shape
2. using graduated cylinder directly
3. by water displacement
Click here for a good summary of ways to find volume
- volume units are liters, milliliters or cubic centimeters
liter = L
milliliter = mL
cubic centimeter = cm3
1 L = 1000 mL
1 cm3 = 1mL = 1cc
Density
- the amount of a substance in a space
Look here for more info
density = mass/volume
Now go to the Resourses page and to the Density experiment
Now try this online quiz
Review mass/volume/ density here
Buoyancy
- determined by comparing the densities of two substance
Now try clicking here for an interactive look at comparing densities
Section 3, Particles of Matter
Atom:
- the smallest particle of an element
- cannot be broken into smaller pieces
- in any element, all of the atoms are
exactly alike and have the same
properties
- two or more atoms can combine to form a compound
- very small
- examples:
- a sheet of paper is 10,000 atoms thick
- there are 2 billion atoms of oxygen in one drop of water
- molecules (click here for more infor on molecules)
- two or more chemically combined atoms
- the smallest part of a compound
that has all the properties of that compound
- examples:
carbon dioxide
sodium chloride
Section 4, Elements from the Earth
Physical and chemical properties can be used to separate (or purify) elements found in earth materials (ores)
examples:
1. How did old time miners find gold?
They filter and wash the dirt (panning)
What two physical properties of gold made this possible?
a)density of gold
b)insolubility in water
2. Iron ore is heated with carbon to produce pure iron. See Figure 18 in text
What kind of a change is this??
chemical change
3. Copper can be separated from some copper compounds with electrolysis see lab p. 36