Large Underground Xenon Dark Matter Search Matthew Szydagis, University of California at Davis.
Matter & Its Properties Ch 1: Lesson 3 Honors ChemistryK. Davis.
-
Upload
myles-randolf-greer -
Category
Documents
-
view
214 -
download
1
Transcript of Matter & Its Properties Ch 1: Lesson 3 Honors ChemistryK. Davis.
Matter & Its PropertiesCh 1: Lesson 3 Honors Chemistry K. Davis
Matter
Matter – anything that has mass and takes up space
Everything around us
Chemistry – the study of matter and the changes it undergoes
Substances
Atoms: the building blocks of all matter
Ions: atoms that become negatively or positively charged
Element: matter containing only one type of atom; ex. hydrogen and oxygen
Four States of Matter
Solidsparticles vibrate but can’t move
aroundfixed shape fixed volumeincompressible
Four States of Matter
Liquidsparticles can move
around but are still close together
variable shapefixed volumeVirtually incompressible
Four States of Matter
Gasesparticles can separate and
move throughout containervariable shapevariable volumeEasily compressedVapor = gaseous state of a
substance that is a liquid or solid at room temperature
Four States of Matter
Plasmaparticles collide with enough energy
to break into charged particles (+/-)gas-like, variable
shape & volumestars, fluorescent
light bulbs, TV tubes
Four States of Matter
Physical Properties
Physical Propertycan be observed without changing the
identity of the substance
Physical Properties
Physical properties can be described as one of 2 types:
Extensive Propertydepends on the amount of matter
present (example: length)
Intensive Propertydepends on the identity of substance, not
the amount (example: scent)
Intensive Physical Properties
The intensive physical properties for a sample of a pure substance remain constant. ex. pure water- always a colorless liquid
that boils at 100ºC at sea level; doesn’t matter if you have 10 mL or 1 L
Melting and boiling point are examples of these constant physical properties. can be used to help identify a substance
Extensive vs. Intensive
Examples:boiling point
volume
mass
density
conductivity
intensive
extensive
extensive
intensive
intensive
Density – a physical property
Derived units = Combination of base units
Volume (m3 or cm3 or mL) length length length Or measured using a
graduated cylinder
D = MV
1 cm3 = 1 mL1 dm3 = 1 L
Density (kg/m3 or g/cm3 or g/mL)mass per volume
DensityM
ass
(g)
Volume (cm3)
Δx
Δyslope D
V
M
Density An object has a volume of 825 cm3 and a
density of 13.6 g/cm3. Find its mass.
GIVEN:
V = 825 cm3
D = 13.6 g/cm3
M = ?
WORK:
M = DV
M = (13.6 g/cm3)(825cm3)
M = 11,220 g
M = 11,200 gV
MD
Density A liquid has a density of 0.87 g/mL. What
volume is occupied by 25 g of the liquid?
GIVEN:
D = 0.87 g/mL
V = ?
M = 25 g
WORK:
V = M D
V = 25 g
0.87 g/mL
V = 29 mLV
MD
= 28.736 mL
Chemical Properties
Chemical Propertydescribes the ability of a substance to
undergo changes in identity
Physical vs. Chemical Properties
Examples:melting point
flammable
density
magnetic
tarnishes in air
physical
chemical
physical
physical
chemical
Physical Changes
Physical Changechanges the form of a substance
without changing its identityproperties remain the same
Ex: cutting a sheet of paper, breaking a crystal, all phase changes
Some Physical Changes
BoilingCondensationDissolvingEvaporationFreezingMeltingSublimation
Phase Changes – Physical
Evaporation =
Condensation =
Melting =
Freezing =
Sublimation =
Liquid -> Gas
Gas -> Liquid
Solid -> Liquid
Liquid -> Solid
Solid -> Gas
Chemical Changes
Process that involves one or more substances changing into a new substanceCommonly referred to as a chemical
reactionNew substances have different
compositions and properties from original substances
Chemical Changes
Signs of a Chemical Changechange in color or odor
formation of a gas
formation of a precipitate (solid)
change in light or heat
Change of Energy
All physical & chemical changes involve a change of energy.
• Endothermic – energy absorbed• a positive number (+) means endothermic• feel cold to the touch
• Exothermic – energy released • a negative number (-) means exothermic• feel warm or hot to the touch
Some Chemical Changes
Combustion Corrosion Electrolysis Fermentation Metabolism Photosynthesis Bubble formation Temperature change Smell Rust
Tip for Distinguishing
Is the change permanent? Can I get the original substance back after the change?” If so, it is a physical change. If not, it is a chemical change.
Physical vs. Chemical Changes
Examples:rusting iron
dissolving in water
burning a log
melting ice
grinding spices
chemical
physical
chemical
physical
physical
What Type of Change?
What Type of Change?
Law of Conservation of Mass
Although chemical changes occur, mass is neither created nor destroyed in a chemical reaction
Mass of reactants equals mass of products
massreactants = massproducts
A + B C
Conservation of Mass In an experiment, 10.00 g of red mercury (II) oxide powder is
placed in an open flask and heated until it is converted to liquid mercury and oxygen gas. The liquid mercury has a mass of 9.26 g. What is the mass of the oxygen formed in the reaction?
Mercury (II) oxide mercury + oxygenMmercury(II) oxide = 10.00 gMmercury = 9.26Moxygen = ?
GIVEN:Mercury (II) oxide mercury + oxygen
Mmercury(II) oxide = 10.00 g
Mmercury = 9.86 g
Moxygen = ?
WORK:10.00 g = 9.86 g + moxygen
Moxygen = (10.00 g – 9.86 g)
Moxygen = 0.74 g
massreactants = massproducts
Matter Flowchart
MATTER
Can it be physically separated?
Homogeneous Mixture
(solution)
Heterogeneous Mixture Compound Element
MIXTURE PURE SUBSTANCE
yes no
Can it be chemically decomposed?
noyesIs the composition uniform?
noyes
Matter Flowchart
Examples:graphite
pepper
sugar (sucrose)
paint
soda
element
hetero. mixture
compound
hetero. mixture
solution
Pure Substances
Elementcomposed of identical atomsEX: copper wire, aluminum foil
Pure Substances
Compound- ex. table salt (NaCl)
composed of 2 or more elements in a fixed ratio
properties differ from those of individual elements
Molecule smallest particle of a compound
Mixtures
Variable combination of 2 or more pure substances that is physically combined.
There is no particular ratio and each part of the mixture keeps its own properties.
Ex. Perfume, potting soil, salad dressings, and tea.
Heterogeneous Homogeneous
Mixtures
Solution Homogeneous mixturevery small particlessubstances are in the same amount in all
parts of the mixtureparticles don’t settleex. rubbing alcohol, perfume
Mixtures
Heterogeneousmedium-sized to large-
sized particlessubstances in the
mixture are not evenly mixed
particles may or may not settle
ex. milk, fresh-squeezed lemonade, salad
dressing, potting
soil
Heterogeneous Mixtures
Colloid: a heterogeneous mixture with larger particles that never settle; scatter light in the Tyndall effect. Ex. Milk
Suspension: a heterogeneous mixture containing a liquid in which visible particles settle
Mixtures
Examples:tea
muddy water
fog
saltwaterItalian salad dressing
Answers:SolutionHeterogeneousHeterogeneousSolutionHeterogeneous
Separating Mixtures
Substances in a mixture are physically combined, so processes based on differences in physical properties are used to separate component
Numerous techniques have been developed to separate mixtures to study components
FiltrationDistillationCrystallizationChromatography
Filtration
Used to separate heterogeneous mixtures composed of solids and liquids
Uses a porous barrier to separate the solid from the liquid
Liquid passes through leaving the solid in the filter paper
Distillation
Used to separate homogeneous mixtures
Based on differences in boiling points of substances involved
Crystallization
Separation technique resulting in the formation of pure solid particles from a solution containing the dissolved substance
As one substance evaporates, the dissolved substance comes out of solution and collects as crystals
Produces highly pure solids Ex. Rocky candy
Chromatography
Separates components of a mixture based on ability of each component to be drawn across the surface of another material
Mixture is usually liquid and is usually drawn across chromatography paper
Separation occurs because various components travel at different rates
Components with strongest attraction for paper travel the slowest