unit 2: matter - boys ranch hs...
TRANSCRIPT
Classifications of Matter
Homogeneous Mixture
Same throughout
Heterogeneous Mixture
Varies in content
Mixtures
Contain more than
one kind of matter
Element
All atoms are the same
Compound
Consists of two or more
types of atoms
Substances
Cannot be separated into different
kinds of matter by physical means
Matter
Anything that has mass and takes up space
Mixtures
• Contain more than one kind of matter
• Can be separated physically
a. Sorting
b. Filtering
c. Heating and cooling
Types of Mixtures
a. Homogeneous mixtures – are the same throughout; every sample has the same ratio of ingredients
Ex: milk
b. Heterogeneous Mixtures – vary throughout; each sample may have a different ratio from the next
Ex: chicken soup
Mixture Examples
• Petroleum (Crude Oil) – 1,000,000 molecular compounds
• Soda – Carbonated water, corn syrup, caramel color, phosphoric acid, natural flavors and caffeine
• Paint – Pigment, Latex, thinning agents
Pure Substances
Cannot be separated by physical means
May contain more than one kind of matter held together by chemical bond
examples: Lithium, NaCl
Types of Substances
a. Elements – Contain only one kind of matter; (one kind of atom)
b. Compounds – contain two or more elements; can be separated chemically
Phases of Matter
gas liquid solid • most movement (high kinetic energy) •shape and size is dependent on the container a liquid is in •Molecules can be compressed closer together • least dense phase
• molecules are touching, but “slide” around each other (FLUID motion) •shape and size is dependent on the container a liquid is in
•molecules are touching and vibrate in place •solids have a definite shape and size
• MOST dense phase
“fluids”
Types of Physical Properties
• Something you can observe or measure without changing the matter into something else.
• For example, you can measure how much something weighs or what it smells like without changing it into something else.
• You cannot tell if something will burn without changing it into something else.
Types of Chemical Properties
• The ability of something to react with something else or to change into something else.
• You cannot observe chemical properties without changing the object into something else.
• For example, if you observe that a nail will rust, it has already changed partially from iron (the nail) into iron oxide (the rust)
Intensive vs. Extensive
• Intensive properties: characteristics that do not depend on the amount of matter present.
– example: density
• Extensive properties: characteristics that depend on how MUCH matter is present
– example: mass
Intensive Properties
• Properties that do not change depending on how much stuff you have.
• These are observable whether you have a lot or a little of it.
• For example, a diamond will be sparkly and lustrous no matter if it is tiny or giant.
Extensive Properties
• Properties that change depending on how much stuff you have.
• These will change if you have a small amount or if you have a large amount.
• For example, a small sample of sand will have less mass than a large sample of sand.
Density
how tightly packed the particles are in a substance (“compactness”)
The relationship of
mass to volume
Intensive or extensive?
• Less dense = float
• More dense = sink
• example: substances that are less dense than water will float on water.
Viscosity
resistance to flow
Viscous fluids are thick and hard to pour
Large molecules flow more slowly (MORE VISCOUS)
Small, smooth molecules flow
more quickly (LESS VISCOUS)
Intensive or extensive?
Malleability A solid’s ability to be
pounded into thin sheets
Ductility
the ability to be made into wire
Intensive or extensive?
Intensive or extensive?
Conductivity
• The ability of a material to conduct electricity, heat, or sound
Intensive or extensive?
Melting Point
• temperature at which a solid melts to beome a liquid
• temperature at which a liquid boils to become a gas
Boiling Point
Intensive or extensive?
Intensive or extensive?
Luster
• how much the surface of a material reflects light (“shine”)
• example: chrome
Intensive or extensive?
Solubility • the ability of one substance to
be dissolved in another substance
• solubility can depend on temperature, pressure, and how much of each substance is interacting
Intensive or extensive?
Reactivity
Copper Reacts with Nitric Acid Magnesium Reacts with
Hydrochloric Acid
Describes how readily a substance will undergo a chemical reaction with another substance
Toxicity
• The degree to which a substance can damage an organism
• While even a small amount of toxins can hurt you, how toxic something is depends on how MUCH there is
Corrosiveness
• A measure of how much a substance can destroy or
irreversibly
damage another
surface or
substance with
which it comes into
contact.
Often strong acids and bases.
7 Sep. 2012 1. Warm Up: by the
door (Classifying and Properties)
2. POP QUIZ!
3. Video: ITP: How to light a Bunsen Burner
4. ½ Class Practice: Bunsen Burner lighting
5. 1/2 Class: Make up work:
- Classification of Matter, #1-13
- Density Practice I, #3-5
- MSDS Exploration
- Density Inquiry Lab (Prob 1 or 3)
6. ITP: Safety Review Video
Physical vs. Chemical
• Physical change - same substance before and after
• Chemical Change – make a new substance
COPY
Examples of Physical Changes
• Shattering glass
• Crushing ice
• Letting ice melt
• Compressing a gas
• dissolving
COPY
Phases or states are: solid, liquid, gas
(and plasma)
changes from one state of matter to
another
based on the addition of or loss of
energy (heat or thermal energy)
Phase Changes (a.k.a. “changes of state)
Phase Changes (a.k.a. “changes of state)
• Melting: solid to liquid
• Boiling or Evaporation: liquid to gas
• Condensation: gas to liquid
• Freezing: liquid to solid
• Sublimation = solid straight to gas!
Chemical Changes
• The result of chemical reactions
• Bonds must be broken and/or created to form a new substance(s)
COPY