matter - anything that has mass and takes up space
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Matter- anything that has mass and takes up spaceThings that are not matter:
Energy Forces
VacuumMagnetic, electric, and gravitational fields
What is Mass?Amount of matter an object has
It is not the same as weight
Weight depends on gravity. It can change depending on where you are, but mass does not change
What instrument can we use to measure Mass?
Balances-triple beam, analytical, pan balance
What are the units for mass?
Kilogram is the SI unit, but we usually use grams in class
Physical Properties:These can be observed without changing the composition of the substance
colormass
melting pointboiling point
density
Melting Point The temperature at which a substance changes from a solid to a liquid
What is the point that a substance changes from a liquid to a solid called?
Freezing Point
Are these points the same?
YES
The name depends on the direction of the change
Boiling Point The temperature at which the vapor pressure of a liquid is just equal to the external pressure on the liquid
DensityThe ratio of mass and volume
VolumeMassDensity
Volume-
the amount of space matter takes up
Units used:Solids:
m3
or any conversions of m
Liquids:
Liters
There is a connection between the solid and the liquid measure
1 cm3 = 1 mL
How is this helpful in getting the volume of an irregular shaped object?
Instruments used to obtain volume:
RulerBeakers
Graduated cylinders
States of MatterSolids
Particles are close togetherDefinite shape and volume
Slight expansion when heatedNot compressible
LiquidsParticles close together, but they move past each other to allow then to flow
Take the shape of containerdefinite volumeTend to expand when heated
Almost incompressible
WaterA special liquid that expands when it freezesThis allows ice to float since it becomes less dense than the liquid form- fish live in the winter
GasesParticles are spaced far apart
Take shape and size of containerEasily compressible
Vapor- a gaseous state of a substance that is a solid or liquid at room temperature
Physical Changes of MatterChanges that do not change the composition of the substancecutting bending
crushing
Changing the state of matter
MixturesPhysical blend of 2 or more substances
Composition may vary- the samples may not be the same
Examples: tea, salt water, alloys
Types of MixturesHeterogeneous
These are not uniform in composition Individual particles or areas can be seen
Examples: salad, sand in water
HomogeneousUniform composition- they look the same throughoutAlso known as solutions which are made by dissolving a solute in a solvent
Examples: tea, coffee, salt water
Phases:These are uniform parts of a mixture
Homogeneous solutions have 1phase Heterogeneous
mixtures have 2 or more phases, each phase with a distinct area
Common Solutions:Gas in Gas: air- composed of CO2, O2, N2, and other gasesLiquid in Gas: water vapor in air,
moistureGas in Liquid: Soda
Liquid in Liquid: vinegar- acetic acid in waterSolid in Liquid: salt water
Solid in Solid: alloys- bronze, brass, steel
Mixtures are physically combined, so they can be physically separatedDistillation: separation of 2 or
more liquids based on boiling pointsMagnets: magnet solid from nonmagnetic solidChromatography: separate liquids based on their solubilities Filtration: solid from a liquid
Decanting: pouring off a liquid from a solid
Centrifuge: separation of solids from a liquid by using an instrument that spins very fast causing the solid to move to the bottom of the tubeDone in medical labs, biology
Evaporation: liquid in a solution is evaporated off leaving behind a solidThis is also called recrystallization
What is a Substance?
Matter with uniform and definite composition
All examples of a substance have the exact same composition
Examples: water, table salt, carbon dioxide
Elements:Types of Substances:
Cannot be broken into smaller substances by chemical means
Represented using 1 or 2 letter symbolsIf 2 letters are used, the first is capitalized and the second is lowercaseExample: O, Cu, Co
Found on the Periodic Table
Compounds:2 or more elements chemically combined
These are separated by chemical means- heating and electricityThe properties of the compound
are different from the elements that make up the compound
Example: Sugar
Represented with formulas that show how many of each element there are in 1 molecule of the compound
Example: Table sugar C12H22O11 has 12 atoms of carbon, 22 atoms of hydrogen and 11 atoms of oxygen
Chemical PropertiesThe ability of a substance to react with another substance to form a new substance OR the inability of a substance to react with another substance to form a new substanceExample: Iron reacts with oxygen to form rust, but aluminum does not react with oxygen to form rust
Chemical Changes:Properties of the substance changes
When a chemical change occurs, you cannot get the original substances back by any physical means
Burning
Cooking
Reacting with another element or compound
Chemical ReactionsWhen 1 or more substances change into a new substanceHow do you know a chemical reaction took place?
Change in TemperatureChange in color or odor
Gas production- bubblesSolid production- precipitate
Representing Reactions:
Reactants Products What goes into reaction
yields The new substance
Example:
2Na + Cl2 2NaCl20 g + 20 g = 40 g
Conservation of Mass
Mass cannot be created or destroyed, so the amount that goes into the reaction must come out
That is why you have a balanced equation
That is why the mass of the reactants is equal to the mass of the products
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