Elements, Compounds, & Mixtures
3.1 ELEMENTS Element- A pure substance that cannot be
separated into simpler substances by chemical or physical means.
Pure Substance- A substance in which there is only one type of particles
PROPERTIES OF ELEMENTS
Each element has its own characteristic properties. These include boiling/melting point, density,
reactivity, flammability, etc.
An element may share one or two properties with another element, but it will not share all its properties with another element. There will be specific properties for each element.
Classifying Elements You can use properties to identify
elements. Think about how many types of dogs
there are. How do you tell one breed from another?
Categories of Elements Metals NonmetalsMetalloids
Classifying Elements Metal- an element that is shiny and
conducts heat and electricity well
PropertiesMalleable – ability to be hammered into sheetsDuctile – ability to be drawn into wires
CLASSIFYING ELEMENTS Nonmetal – an element that conducts
heat and electric poorlyProperties
1. dull 2. brittle – not malleable
Metalloid- an element that has properties of metals and nonmetalsProperties
1.some are shiny
2. some are dull
3. somewhat malleable and ductile
4. some are good conductors of heat and electricity
5. some are poor conductors of heat and electricity
CLASSIFYING ELEMENTS
CLASSIFYING ELEMENTS Appearance Conductivity Physically Example
Metal
Shiny
Good
malleable., ductile
Lead, Copper
Nonmetal
Dull
Poor
Brittle
Sulfur, oxygen
Metalloid
Some Shiny/ some dull
Some good/ some poor
Somewhat malleable and ductile
Silicon, boron
3.2 COMPOUNDS Compound- a substance made up of atoms
of two or more different elements joined by chemical bonds Examples: H2O (water), NaCl (table salt)
A particle of a compound is called a molecule Elements do not randomly combine. They join into a
specific ratios according to their masses.
PROPERTIES OF COMPOUNDS Each compound has its own physical
properties and chemical properties. The properties of a compound are
different from the properties of the elements that form it. Sodium + Chlorine Table
Salt Explosive soft metal Yellow Piousness Gas
BREAKING DOWN COMPOUNDS Some compounds can be broken down
into their elements or simpler compounds by chemical means.
Sometimes energy in the form of heat is needed to do this.
3.3 MIXTURES Mixture- A combination of two or more
substances that are not chemically combined.An example would be a salad (or salsa as in
the picture). The cheese, sauce, and dough are still the same items after you make the pizza.
PROPERTIES OF MIXTURES Sometimes you cannot see all the
components like in salt water This is called a homogeneous mixture. It includes salt and water.Since mixtures are not chemically
combined, you can separate the different substances by physical methods.
Components in a mixture do not need to be in a specific ratio.
SEPARATING MIXTURES Sometimes you can just pick ingredients
out of a mixture (pizza) Other ways to separate mixtures include:
evaporation – separates a mixture based on boiling points Ex: salt in water
magnet – anything ferromagnetic will stick to the magnet EX. Iron & Aluminum nails in box
distillation – separates a mixture based on density. Ex: crude oil – gasoline & propane
centrifuge – separates based on particle size Ex: blood
COMPOUNDS VS. MIXTURES
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 by using any ratio
of components
Formed using a set ratio
of components
MIXTURE VS. COMPOUND VS. ELEMENT
SOLUTIONS, SUSPENSIONS, & COLLOIDS
SOLUTIONS Solution- A mixture that appears to be a
single substance. Particles are small & cannot be filteredSolutions have the same composition
throughout.Example: Salt Water
Solute- Substance that is dissolved. (Salt) Solvent- The substance in which the solute is
dissolved. (water)
SOLUTIONS CONTINUED The term soluble means able to
dissolve. Insoluble means unable to dissolve.Solutions can be solids, liquids, or gases.
Solubility- Measure of the amount of solute dissolved in a solvent. This is expressed as g/mLTo increase solubility:
heat stir crush – smaller particles
COLLOIDS Colloid A type of mixture in which the
particles are dispersed throughout but are not heavy enough to settle outParticle size is larger than that of a solution
but small enough they will still pass through a filter.
Examples of colloids: milk, fog
COLLOIDS Colloids scatter light. (fog) You can actually
see the beam of light in the colloid.
SUSPENSIONS Suspensions- A mixture in which the
particles of a material are dispersed throughout a liquid or gas but are large enough that they settle out.Particles are large enough to settle out.Suspensions can be separated by passing
through a filter.Examples: Italian salad dressing, muddy
water
ELEMENTS, COMPOUNDS, MIXTURES
Elements Compounds Mixtures
How many parts make it up?
1 2 or more 2 or more elements or compounds
Pure: more than one substance?
pure pure Not pure
Chemically or physically combined?
N/A Chemically physically
Chemical change to make them?
N/A Yes no
Fixed ratio? N/A Yes no
How separated: chemically/physically?
N/A Chemically physically
SOLUTION, SUSPENSION, COLLIOD
Elements Compounds Mixtures
How many parts make it up?
1 2 or more 2 or more elements or compounds
Pure: more than one substance?
pure pure Not pure
Chemically or physically combined?
N/A Chemically physically
Chemical change to make them?
N/A Yes no
Fixed ratio? N/A Yes no
How separated: chemically/physically?
N/A Chemically physically
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