pure substances, mixtures, and solutions · either compounds or elements. matter heterogeneous...
TRANSCRIPT
Pure Substances, Mixtures, and
Solutions
Separating Matter into 3 classifications:
•Pure substance: matter that has a fixed (constant) composition and unique properties. Contains only 1 type element or compound; homogeneous
Mixture: Contains at least 2 PHYSICALLY
combined compounds; can be homogeneous
or heterogeneous
Homogeneous Substances• Means same throughout
1) element: only 1 type of atom
2) compound: 2 or more CHEMICALLY combined elements (not easily separated from each other)
ex: water, CO2
3) Solution: a special kind of mixture 2 phases/parts (SOLUTE dissolves & SOLVENT does the dissolving)
ex: moist air (H2O in Air); sterling silver (Cu
in Ag…called an alloy)
Heterogeneous matter
• Means different throughout
• Always a MIXTURE (solutions are mixtures that are NOT heterogeneous)
• 2 or more PHYSICALLY combined substances (elements/compounds)
• ex: blood, air, muddy water
Separating Matter into 3 classifications:
•Matter can also be classified according to its composition. Mixtures can be homogeneousor heterogeneous.
•Mixtures can be separated into pure substances, and pure substances can be either compounds or elements.
MATTER
Heterogeneous
mixture
Is it uniform
throughout?
No
Homogeneous
Yes
Can it be separated
by physical means?
Pure Substance Homogeneous
Mixture (solution)Can it be decomposed
into other substance by
a chemical process?
Element Compound
No yes
No yes
ElementsPure substance
Only one type
of particle
Called Atoms
Characteristic PropertiesBoiling
Point
Melting
Point
Density Chemical
Properties
EX:
reactivity
with acid
Categories
Metals
Nonmetals
Metalloids
Help you identify
a specific element
Element – a substance that cannot be separated or broken down into simpler
substances by chemical means.
Pure Substance – a sample of matter, either a single element or a single
compound, that has definite chemical and physical properties.
Metal – an element that is shiny and that conducts heat and electricity well.
Nonmetal – an element that conducts heat and electricity poorly.
Metalloid – an element that has properties of both metals and nonmetals.
Section 1
* Lab
* 2 wksts
* Quiz
Notes
Compounds
EX: Mass of Hydrogen
to the mass of Oxygen
in water is 1 to 8 or 1:8
Compound – a substance made up of atoms of two or more different
elements joined by chemical bonds.
Pure substance
Made of elements
Chemically
combined
Elements join
in specific ratios
Properties
Physical
Chemical
Used to identify
compounds
Ex: Sodium reacts violently with water.
Chlorine is a poisonous gas.
Combined they make sodium chloride
(table salt)
Use chemical
change to break
down to elements
or simpler
compounds
Add energy by
heat or electricity
Found everywhere
Food
Clothing
Aluminum
oxide
Ammonia
Proteins
Carbon dioxide
carbohydrates
Section 2
* Lab
* Quiz
Notes
Familiar Compounds
Compound Elements combined
Table Salt Sodium and Chlorine
Water Hydrogen and Oxygen
Vinegar Hydrogen, Carbon, and
Oxygen
Carbon Dioxide Carbon and Oxygen
Baking Soda Sodium, Hydrogen,
Carbon, and Oxygen
Section 2 Notes
MixturesProperties
Mixture – a combination of two or more substances that are not chemically
combined.
Suspension – a mixture in which particles of a material are more or less evenly
dispersed throughout a liquid or gas.
Colloids – a mixture consisting of tiny particles that are intermediate in size
between those in solutions and those in suspensions and that are suspended in a
liquid, solid or gas.
No chemical
changes
happens
Some are easy
to separate,
some are hard
Ex:
Pizza toppings,
salt water
No
specific
ratio
Suspensions
Solutions
Colloids
Particles
are large
enough to
settle and
scatter/block
light
Can be
separated
by filtering
Ex: Snow Globes
Salad dressingParticles are smaller
than in a suspension
Ex:
Milk,
Mayo,
Gelatin,
Whipped
cream
Can’t be
separated
by filtering
doesn’t
settle out
Section 3
* 4 worksheets
* Lab
* Test
Notes
Mixtures and Compounds
Mixtures Compounds
Made of elements,
compounds, or both
Made of elements
No change in original
properties of
components
Change in original
properties of
components
Separated by physical
means
Separated by chemical
means
Formed using any ratio
of components
Formed using a set ratio
of components
Section 3 Notes
Solutions* Appears to be a
single substance.
* Particles don’t
settle – very small
* Doesn’t scatter light.
Substances
that dissolve:
Solute
Substance in which
another substance
is dissolved or
the larger amount of
liquid or gas:
Solvent
Solution – a homogeneous mixture of two or more substances uniformly
dispersed throughout a single phase
Solvent – in a solution, the substance in which the solute dissolves.
Solute – in a solution, the substance that dissolves in the solvent.
Soluble – able to dissolve
Insoluble – unable to dissolve
Substances must
be soluble to create
a solution.
Ex: salt water
Alloys:
solid solutions
metal & metal or
nonmetal & nonmetal
Section 3 Notes
Examples of Different States of Solutions
States Examples
Gas in gas Dry air (oxygen in
nitrogen)
Gas in liquid Soft drinks (carbon
dioxide in water)
Liquid in liquid Antifreeze (alcohol in
water)
Solid in liquid Salt water (salt in water)
Solid in solid Brass (zinc in copper)
Section 3 Notes
Concentrations of Solutions
Concentration – the amount of a particular substance in a given quantity of a
mixture, solution, or ore.
Dilute – a solution with less solute.
Concentrated – a solution with more solute.
Solubility – the ability of one substance to dissolve in another at a given
temperature or pressure.
Expressed in
grams of solute
per milliliter
of solvent
either
Dilute Concentrated
Does not tell the amount
of solute dissolved
Solubility
Ex: just the right
amount of sugar
can be completely
dissolved in water
Dissolving
Gases
in Liquids
Less soluble as
temperature is raised
Ex. Soft Drinks
go ‘flat’ faster when
they are warm.
Dissolving
Solids faster
in Liquids
Mixing
Heating
Crushing
Section 3 Notes