Exam 1 vocab
Terms
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- matter
- anythign w. mass that takes up space
- substance
-
smallest particle-all samples are identical
element or compound - element
- all atoms of one element have the same # of protons
- compound
- chemical combination of elements, can NOT be separated by physical means
- mixture
-
combination of elements
CAN be separated by physical means
(evaporation, magnetism etc) -
heterogeneous
homogeneous -
hetero--uneven mixture, not all samples are the same
homo-all samples are the same, evenly spread -
solid
liquid
gas -
solid- little movement of atoms, definite shape and volume
liquid- movement of atoms, definite volume
gas-lots of movement of atoms, indefinite shape and volume -
chemical change
physical change -
chem-changes the way atoms are bonded, creates a new subs
phys-change in the physical state (solid, liquid, gas) - atom
- smallest particle of an element
-
atomic mass
atomic number
mass number
atomic mass unit -
atomic mass--avg mass of all naturally occuring isotopes
atomic number- # of prortons, identity of atom
mass #-# of protons plus # of neutrons
Atomic mass unit (amu)-weight of proton/neutron--1/12 of Carbon-12 -
proton
neutron
electron -
proton-wieght of 1 amu, positively charged, found in the nucleus
neutron-no charge, in the nucleus, weight of 1 amu
electron-negativley charged,little weight, orbits nucleus - isotope
- atoms with the same atomic mass, but different mass numbers. Atoms of the same element with different numbers of neutrons
-
Fusion
Fission -
Fusion-2 nuclei combine to create one larger nucleus
Fission-One nucleus splits off into two smaller nuclei, often emits stray neutrons - radiocactive decay
- Hw unstable nuclei achieve stability
-
alpha
beta
positron
gamma -
alpha-emits alpha particle
atomic # -2
mass # -4
beta-emits beta particle
atomic # +1
mass # 0 change
Positron-emits positron
atomic # -1
mass # 0 chage
Gamma-emits energy - half-life
- The amount of time it takes for half a sample of a given substance to decay
- Where is most of the mass of an atom?
- Nucleus
- What particles are heavy? light?
-
Protons and Neutrons are heavy
electrons are light - Why does the nucleus stay together?
-
protons repel eachother BBUT
nuclear force (is stonger) attracts protons and neutrons to eachother - What makes a nucleus stable?
-
small isotopes # of neutrons (N) = number of protons (Z)
large isotopes
N/Z =1/1.5 - Law of Conservation of Mass, Energy
- Mass and energy cannot be creeated or destroyed EXCEPT in nuclear reactions, when mass and energy are interchangeable
- (change in)e=(change in)mc2
-
c=speed of light (3*10^8 m/s)
m-mass
e=energy - Mass Defect
-
if mass goes down, energy goes up
if energy goes down, mass goes up - Einstein
-
e=mc2
energy and mass are interchangeable
time is dependent on the speed of light - Faraday
-
electromagnetism
light=electromagnetic wave - Lavoisier
-
law of conservation of mass
interchangeable physical states
separated hydrogen and oxygen - Meitner
-
discovered fission
atoms can be broken up - Divisions of matter
-
Matter --> substance & muxture
Substance-->element & compound
Mixture-->homogeneous & heterogeneous
homogeneous mixture=solution