Download I. Properties of Matter

I. Properties of Matter
1. Substance (pure substance):
matter that has a uniform and
unchanging composition
• Water (H20)
• Table salt (NaCl)
• Gold (Au)
I. Properties of Matter
2. Element – a pure substance that
cannot be separated into simpler
substances by physical or chemical
means
• 91 naturally occurring elements on
Earth
• Gold (Au), Aluminum (Al), etc.
I. Properties of Matter
3. Compound – another type of pure
substance – a combination of two or
more different elements that are
combined chemically
• Can be separated into elements
• H20, CO2, etc.
I. Properties of Matter
4. Law of Definite Proportions – states
that, regardless of the amount, a
compound is always composed of the
same elements in the same proportion
by mass
• H2O (water) always has two hydrogen
atoms and one oxygen atom.
• If it doesn’t, then it isn’t water.
I. Properties of Matter
5. Percent by Mass – the ratio of the
mass of each element in a compound
to the total mass of the compound –
expressed as a percent
mass of element
Percent by mass (%) =
mass of compound
x 100
I. Properties of Matter
6. If a 20.00 g sample of sucrose (sugar)
contains 8.44 g of carbon, 1.30 g of
hydrogen, and 10.26 g of oxygen,
what is the percent by mass of each of
the elements in the compound?
I. Properties of Matter
7. Law of Multiple Proportions – states that
when different compounds are formed by a
combination of the same elements, different
masses of one element combine with the
same relative mass of the other element in
a ratio of small whole numbers
•
•
H2O (water) and H2O2 (hydrogen peroxide)
There are two hydrogen atoms in both
compounds but different numbers of oxygen
atoms
I. Properties of Matter
8. Physical property: a
characteristic that can be
observed or measured without
changing the sample’s
composition
• Density, color, odor, taste, hardness,
melting point, boiling point, etc.
I. Properties of Matter
9. Two types of physical properties:
a. Extensive properties: dependent
upon the amount of substance present
• Mass, length, volume, etc.
b. Intensive properties: independent of
the amount of substance present
• Density, appearance, state of
matter, etc.
I. Properties of Matter
10. States of matter: the physical forms
in which all matter naturally exists on
Earth
a. Solid – has definite shape and volume
b. Liquid – flows, has constant volume,
takes the shape of its container
c. Gas – flows, takes the shape of its
container, fills entire volume of its
container
I. Properties of Matter
11.Vapor: the gaseous state of a
substance that is a solid or a
liquid at room temperature
I. Properties of Matter
12.Chemical property: the ability (or
inability) of a substance to
combine with or change into one
or more other substances
• The ability of iron to form rust when
combined with oxygen is a chemical
property of these elements.
II. Changes in Matter
1. Physical change: a type of
change that alters the physical
properties of a substance but
does not change its composition
• Melting an ice cube
• Crushing a solid chemical into powder
II. Changes in Matter
2. Chemical change (Chemical
reaction): a process involving
one or more substances changing
into new substances
• Burning, corroding, rusting, fermenting,
etc.
II. Changes in Matter
3. Law of Conservation of Mass:
states that mass is neither created
nor destroyed during a chemical
reaction, but is conserved
Massreactants = Massproducts
III. Mixtures of Matter
1. Mixture: a combination of two or
more pure substances in which
each pure substance retains its
individual chemical properties
• Example: salt water (The salt and
water can be separated, so we know
that they retain their individual
chemical properties.)
III. Mixtures of Matter
2. Types of mixtures:
a. Heterogeneous mixture: does not
blend smoothly throughout
• Example: sand and water
b. Homogeneous mixture (solution):
has constant composition throughout;
may contain solids, liquids, or gases
• Examples: lemonade, air, alloys
• Particles won’t settle to bottom
III. Mixtures of Matter
c. Colloid – a type of mixture that never settles
(particles are larger than those in solutions
but not heavy enough to settle)
• Example: milk (contains water, fats, and
proteins in varying proportions)
d. Suspension – a type of heterogeneous
mixture containing particles that settle out if
left undisturbed
• Example: muddy water
III. Mixtures of Matter
3. Methods of separating mixtures:
a. Filtration – uses a porous barrier
(filter) to separate a solid from a liquid
b. Distillation – heating a mixture and
collecting the condensation as the
components turn to vapor
• Different substances have different
boiling points, so they turn to vapor at
different times during the heating
process.
III. Mixtures of Matter
c. Crystallization – when a solution can’t hold
any more of a dissolved substance, the
addition of a tiny amount more causes the
substance to come out of solution to form
crystals
•
•
Rock candy
Stalactites and stalagmites in caves
d. Chromatography – separating the
components of a mixture by drawing/pulling
them across the surface of another material
•
Black ink in markers can be separated into the
colors of the spectrum
III. Mixtures of Matter
4. Tyndall effect – the phenomenon
where particles in a colloid scatter light
• Used to tell the difference between
solutions and colloids
IV. Periodic Table
1. Periodic Law – states that there is a
periodic repetition of chemical and
physical properties of the elements
when they are arranged by increasing
atomic number
2. Russian chemist Dmitri Mendeleyev
developed the first version of the
periodic table in 1869.
IV. Periodic Table
3. Main Group (Representative)
Elements – groups designated with
an A (1A through 8A), which possess a
wide range of chemical and physical
properties
IV. Periodic Table
4. Transition Elements – groups designated
with a B (1B through 8B); further divided
into transition metals and inner transition
metals
5. Two sets of inner transition metals:
lanthanide and actinide series – located
along the bottom of the periodic table
6. A more recent numbering system, which
uses the numbers 1 through 18, also
appears above each group.
IV. Periodic Table
7. Metals – elements that are generally
shiny when smooth and clean, solid at
room temperature, and good
conductors of heat and electricity
8. Alkali Metals – group 1A elements
(except for hydrogen)
9. Alkaline Earth Metals – group 2A
elements
IV. Periodic Table
10. Nonmetals – elements that are
generally gasses or brittle, dull-looking
solids; poor conductors of heat and
electricity
11. The only nonmetal that is a liquid at
room temperature is bromine (Br).
12. Halogens – the highly reactive group
7A elements
IV. Periodic Table
13. Noble gases – extremely unreactive
group 8A elements
14. Metalloids – elements with physical
and chemical properties of both metals
and nonmetals; these border the “stair
step” between the metals and
nonmetals
IV. Periodic Table
15. A column on the periodic table is
called a group or family.
16. A row on the periodic table is called a
period.