Transcript Solute

CP Chemistry
Chapter 2
Matter and Change
• Matter – anything that has mass and
takes up space
• Mass- amount of matter an object
contains
• Materials – differ in type of matter they
are composed of
Properties of matter – physical
and chemical
Physical property – quality or
condition of a substance that can
be observed or measured without
changing the substance’s
composition
Examples of Physical Properties
 Color
 Odor
 Hardness
 Density
 Solubility
 Melting
point, boiling point, freezing
point
 Physical state – solid, liquid, gas
States of matter
• Solid (s) definite shape and volume
• Liquid (l) definite volume, no
definite shape
• Gas (g) no definite shape, no
definite volume
• Plasma – we don’t deal with
Phase
Differences
Solid – definite volume and shape; particles packed
in fixed positions.
Liquid – definite volume but indefinite shape;
particles close together but not in fixed positions
Gas – neither definite volume nor definite shape;
particles are at great distances from one another
Plasma – high temperature, ionized phase of matter
as found on the sun.
Gas and vapor not the same
Gas – normally exists that way at
room temperature
Vapor – gas state of a substance that
is normally a liquid or solid at room
temperature
Chemical Property
• The ability of a substance to
undergo chemical reactions and to
form new substances
• Rusting, burning, fermenting,
exploding, rotting, decomposing
• Iron and sulfur example
Changes in matter
• Physical change - A change
which alters a material
without changing its
composition
• Cutting, grinding, melting,
boiling, freezing, dissolving
Chemical Change
• Change which results in one or
more new substances being formed
• The new substance has different
chemical properties!!!
• Examples
• Paper burns, iron rusts, silver
tarnishes
• All physical and chemical changes
involve a change in ENERGY
• Energy is the ability to do work
or produce heat
Indications that a
chemical reaction has
occurred
• Energy released or absorbed
• Color change
• Odor released
• Production of a gas
• Irreversibility
• Formation of a solid
(precipitate)
Mixtures
Physical blend of two or more
substances
Composition can vary
2 types:
Heterogeneous
Homogeneous
Heterogeneous Mixture
Not uniform in composition
Has 2 or more phases
Phase – any part of a system
with uniform composition and
properties
Dirt, salad, paper, rocky road
ice cream
Homogeneous Mixture
 Has
a completely uniform
composition
 All components are evenly
distributed
 Consists of a single phase
 Called a SOLUTION
Solutions contain a SOLVENT and one or
more SOLVENTS
 SOLVENT – substance that the solute is
dissolved in. Is usually the substance
present in the largest amount
 SOLUTE – the substance that dissolves in
the solvent to make the solution

Solution – what do you think of?
• Can be gas, liquid, or solid!!!!!
• Can you think of any
examples?
Solutions
Gas solution
AIR
Solute – oxygen, carbon
dioxide, other gases
Solvent – nitrogen gas
Liquid solution
Rubbing alcohol
Solute – isopropyl alcohol
(liquid)
Solvent – water (liquid)
Another Liquid solution
Saltwater
Solute – salt (solid)
Solvent – water (liquid)
Solid solution – any alloy
 BRASS
 Solute – zinc (solid)
 Solvent – copper (solid)
 STAINLESS STEEL
 Solute – chromium, nickel (solids)
 Solvent – iron (solid)
Separating mixtures
Use PHYSICAL methods (no
chemical changes involved)
 Magnet, sifting,
 Liquid mixtures – distillation
Matter made up of Atoms
Made up of protons, neutrons, and
electrons
Protons – have a positive charge
Neutrons – no charge
Electrons – negative charge
In a neutral atom, #protons =
#electrons
Protons and neutrons –
packed in a tiny NUCLEUS
Electrons – move around the
nucleus in an “electron cloud”
Chemical bond is formed
when two atoms share or
transfer electrons
Substances
Can be elements or compounds
 Element – substances made up of only
one kind of atom
 Every element has a unique atomic
number
 Atomic number – number of protons in
the nucleus
Atom is the smallest
particle of an element
that has the properties
of that element
 Are at least 111 officially named elements
 About 90 are naturally occurring
Chemical symbol is used to
represent each element
 Has one or two letters, first letter is always
capitalized
 Compound – 2 or more elements that
have been CHEMICALLY combined.
 Can only be separated by CHEMICAL
means – chemical reaction must take
place
Periodic Table
 Gives names and symbols of all the
elements
 In order of increasing ATOMIC
NUMBER
 Two main divisions:
 Metals – left of “step”
 Nonmetals – right of “step”
Most of the elements that touch the
step are called METALLOIDS or
SEMIMETALS
(exception is Al (aluminum). It is a
METAL
Metals
Shiny solids
Exception is Hg (Mercury) is a
LIQUID
Good conductors of heat and
electricity
Malleable
ductile
Nonmetals
Gases or dull solids (not shiny)
Exception is Br (Bromine) is a
liquid
Poor conductors of heat and
electricity
Metalloids (Semimetals)
 Some properties of both metals and
nonmetals
 Good as computer components (only
conduct electricity when heated)

3 categories
 Monatomic (most elements) – exist as
single atoms. Fe, Al, S
 Diatomic – exist in pairs when not
bonded with other elements
 Are 7 – easy to remember!
H, N, O, F, Cl, Br, I
 H2, N2, O2, F2, Br2, I2

 Polyatomic
A
few elements exist as groups
of 3 or more atoms
 O3
P4
 Number
written to the right and below
the line
 Shows the number of atoms of that
element in that element or compound
 H2, N2, O2, F2, Cl2, Br2, I2
 P4
 O3
 Consist
of two or more kinds of
atoms that are chemically
bonded
 H2O, NaCl, NaHCO3 (baking soda)
Used to represent compounds
 Is a group of symbols that shows the
number and kinds of elements in that
compound
 Shows the DEFINITE makeup of the
compound
 NaCl
1 Na 1 Cl
 H2O
2H
1O

 C12H22O11
(sucrose) (table sugar)
 12 C atoms
 22 H atoms
 11 O atoms
 Smallest unit of sucrose has a total
of 45 atoms
Parenthesis means you have 2 groups of
NH4
 So…….
 Name and number of types of atoms….
N
2
H
8
C
1
O
3

Ca
5
P
3
O
 12
F
1

To separate a compound to its elements,
the compound must be CHEMICALLY
changed
 Forming and separating compounds
require CHEMICAL reactions to occur

Matter
substance
element
mixture
compound
heterogeneous
homogeneous