matter and energy Flashcards
matter
anything that takes up space and has mass
- exists in three phases: solid, liquid, and gas
solid phase
-
definite volume and definite shape
- crystalline
- packed tightly
liquid phase
-
definite volume and no definite shape
- some disorder
gas phase
-
no definite volume and no definite shape
- total disorder = entropy
changes that can affect phases (these changes are physical changes)
- temperature - affects how fast particles move
- affects how packed the particles are
endothermic
process that requires absorption of heat (heating process)
exothermic
process that involves the release of heat (cooling process)
endothermic changes (heat is absorbed)
- melting (solid to liquid)
- vaporization / evaporation (liquid to gas)
-
sublimation (solid to gas) – skips the liquid phase
- ex: dry ice and iodine
1) CO2 (s) => CO2 (g)
2) I2 (s) => I2 (g)
- ex: dry ice and iodine
exothermic changes (heat is released)
- freezing (liquid to solid)
- condensation (gas to liquid)
- deposition (gas to solid)
matter (categorizing matter)
- cannot be created nor destroyed, only change form
- anything which occupies space and has mass
- in chemical reactions the mass, charge, and energy of all matter are ALL conserved
pure substance
a type of matter that has definite composition and the properties are the same throughout
elements
made of one kind of atom
- CANNOT be broken down by ordinary means
ex: Au, Mg, Na or Diatomic Elements
compound
a substances made of two or more elements that are chemically combined
ex: 2H2 + O2 => 2H2O
mixture
physical combination of two or more distinct substances; compostion ALWAYS VARIES
ex: air, milk, sand, and glass
ex: NaCl (aq)
properties of a mixture:
1. formed by a physical combination
2. parts of a mixture retain their og properties
3. parts are separated by physical properties (ex: magnetism, density, size, boiling point)
4. NO definite formula; composition varies
homogenous
mixtures were all parts look the same and particles are evenly distributed
- ex: air, milk, NaCl (aq)
heterogeneous
a mixture where you can see the parts and the particles are unevenly distributed
- ex: rocks, soil, and sand
physical properties
characteristics which can be observed without producing a new substance
- ex: color, odor, taste, density (d=m/v)
solubility
ability to dissolve (forms a mixture)
brittleness
ability to shatter when struck
luster
shine
magnetism
ability to be attracted to a magnet
malleability
ability to be hammered into a sheet and not fall apart
- ex: aluminum foil
ductility
ability to be drawn into a wire
conductivity
ability to carry a current or heat
tenacity
ability to resist being pulled apart
sublimation
can change from a solid to a gas without melting at a certain temperature
boiling point
temp at which liquid turns to a gas
melting point
temp at which solid turns to a liquid
chemical properties
characteristics which describe how a substances reacts and fails to react with other substances
physical change
a change in the appearance but NOT in major properties or composition
- ex: H2O (s) + heat => H2O (l)
- boiling evaporation
- phase changes
- grinding / chopping
- dissolving
chemical change
a change in which one or more substances form with totally new properties and compounds
- burning
- digestion
- rusting / corrosion (oxidized)
- souring of milk
- decaying
filtration (size)
used to separate misture components based on SIZE (heterogenous mixture)
- small particles (filtrate) pass through the filter paper
- large particles (residue) remains on the filter paper
density
a separatory funnel is used to separate parts of a mixture based on differences in DENSITY
paper chromatography
separates a mixture basted on different attractions to the paper
- molecules has a difference in charge/polarity
distillation (boiling point)
used to separate homogenous mixtures based on boiling points
- solid dissolved in liquid
- two or more liquids combined
temperature
the measure of the average kinetic energy (energy of motion) of a substance’s particles
- measured in fahrenheit, celsius, and/or kelvin
heat
the amount of energy transferred from on substances to another
- measured in joules or calories
- moves from a higher temp to lower temp
absolute zero
temp at which all molecular motion stops
kinetic energy
energy of motion; increases as temp increases
potential energy
stored energy in bonds; increases as the distance between the molecules increases
specific heat
amt of hear energy in joules required to change the temp of 1 gram of a particular substance by 1 degree (J/g ⋅ °C )
- specific hear of water = 4.18 J/g ⋅ °C
measurement of heat energy
Q = mCΔT
1. Q = amt of heat gained or lost (joules / J)
2. m = mass (grams)
3. C = specific heat of a substances (J/g ⋅ °C )
4. Delta T = change in temp (final - intial)
heat of fusion
amt of heat (J/g) required to melt 1 gram of a substance
- equal to freezing
Q = m x Hf
heat of vaporization
amt of heat (J/g) required to vaporize 1 gram of a substance
- equal to condensation
**Q = m x Hv
