chapter 2 Flashcards
whats matter
anything with mass that takes space {i.e. water, wood, and plastic bags}
pure substance
has a fixed or definite compostion composed of 1 type of atom
mixtures
has two or more different substances that are physically mixed NOT CHEMICALLY COMBINED
compound
composed of 2 or more elements always combined in same proportion (a definite ratio) I.e. hydrogen peroxide (H2O2)
elements
a pure substance only has 1 type of material ie copper cu
can mixtures be seperated
yes by physical methods i.e. spaghetti and water via strainer
how are mixtures of liquids + solids seperated
by filtration or using chromatography paper as they travel at diff rates up the surface you can actually see them
what are homogenous mixs
the comp is uniform throughout and you cant tell the different parts in the mix
examples of homogenous mixtures
scuba breathing mixtures i.e. nitrox (oxygen and nitrogen gases)
heterogenous mixtures
comp varies from one part of the mix to another diff parts of mix are visible i.e. water and copper
which is a pure substance or a mixture
a. pasta and tomato sauce
b. aluminum foil
c. helium
d. air
a. mix
b.pure substance
c. pure substance
d. mix
3 states of matter
solid, liquid, or gas
solids have
definite shape, volume, particles held close together by strong attractive forces , particles arranged in rigid pattern, can only vibrate slowly in fixed positions i.e. amethyst
liquids have
definite volume but not definite shape, have same shape as container, particles that move slowly in random directions
gases have
indefinite shape, volume, same shape and volume as container, particles far apert, move at high speeds, have littles attraction to one another
physical properties
characteristics observed or measured without changing substance identity i.e. shape, physical state, boiling/freezing points, density, color of substance
physical properties of copper
reddish orange color, shiny, excellent conductor of heat and electricity, solid at 25 degrees Celsius, melting point 1083 degrees Celsius, boiling point 2567 degrees Celsius.
physical change
matter going physical state of change but composition remains constant i.e. water had 3 states ice, water, steam
physical changes also can change physical appearance
i.e. salt is dissolved in water salt crystals no longer visible but can reform with evaporation
chemical properties
chemical prop descr. ability of a sub. to interact w/ other sub. and to change into a new sub.
chemical change
when this occurs orig. sub. turned into 1 or more new sub. w/ new physical and chem prop.
chem change what happens
new comp, new physical properties, new chemical prop i.e. iron nails corrode in water and a new sub forms called rust
defibriliater
provides energy to restore bodies cardiac function
energy is
bodies ability to do work can be kinetic or potential
kinetic energy
energy of motion
potential energy is
determined by the positions of an objects or its chemical comp.
identify the energy in each example as potential or kinetic?
a. rollerblading
b. a peanut butter and jelly sandwhich
c. mowing the lawn
d. gas in the gas tank
a. kinetic
b. potential
c. kinetic
d. potential
heat is
energy associated with the motion of particles and the faster they move the greater the heat or thermal energy of the substance si unit of energy and work is the joule (j)
1 kj = 1000 j
carbs
when carbs are exhausted fats and then proteins are used for energy
calorimeters measure energy valies
they determine the energy value for the food
changes of state are
melting, freezing, boiling, condensation, and sublimation and deposition.
change of state happens when
it is converted from 1 state to another at a constant temp
melting is
when it changes from a solid to liquid at its melting point (mp)
freezing is
when it changes from a liquid to a solid at its freezing point (fp)
sublimination
the particles in the surface of a solid change directly to a gas without going through the liquid state no change in temp
deposition
reverse of sublimination and gas particles change directly to a solid dry ice is an ex
evaporation
happens when water molecules gain sufficient energy to escape the liquid surface and enter gas
boiling point
molecules have enough energy to overcome their attractive forces and become a gas
condensation
water vapor is converted to a liquid as the water molecules lose kinetic energy and slow down occurs at same temp as boiling but heat is removed
vaporization and condensation are
reversible processes
