first test Flashcards
Matter
anything that has mass and takes up space
mass
amount of matter that an object contains
mass v. Weight
weight is the measure of pull of gravity on object and mass is amount of matter the object contains - mass is constant throughout universe and weight is subjective to where you are in the universe
Volume
the amount of space an object takes up
what does matter make up
everything
how can properties of matter classified?
they can be classified as intensive or extensive
Extensive Properties
extensive property is a property that depends on the amount of matter in a sample, such as mass and volume
Intensive Properties
property that depends on type of matter in sample, not amount of matter - every sample of a given substance should have the same intensive properties
Substance
matter that has a uniform and definite composition
pure substance
contains only one type of matter(is NOT a mixture, one type of element, or compound ) basically only one type of particle
Physical property
condition or quality of a substance that can be measured or observed while not making any chemical changes to the substance - physical changes are ok
examples of physical properties (7)
(hardness, color, conductivity, malleability, Density, Melting Point, Solubility)
3 states of matter
solid liquid gas
solid(4)
- particles packed close together
- almost in-compressible,
- expands only slightly when heated,
- shape does not depend on shape of container
Liquid (5)
- particles contact one another but not packed in rigid arranged
- almost incompressible
- expand moderately when heated
- has no independent shape, takes on shape of its container
- it can flow
Gas (3)
- has indefinite volume and shape
- it is compressible
- Expands greatly when heated
Vapor
substance in its gaseous state that is ordinarily a liquid or solid at room temperature
Physical change
some properties of material can change, but composition does not change
liquid to gas transition
evaporation
what are the two types of physical changes?
reversible or irreversible
gas to liquid transition
condensation
solid to liquid transition
melting
liquid to solid transition
freezing
solid to gas transition
sublimation
gas to solid transition
deposition
mixture
physical blend of two or more substances - can be physically separated into its components
what are the two types of mixtures?
heterogeneous and homogenous
heterogeneous mixtures
have not uniform composition mixture
homogenous mixtures
uniform composition mixture
solution
homogenous mixture
element
substance that cannot be broken down into simpler substances under normal laboratory conditions - simplest forms of matter
compound(3)
-substance that can be separated into simpler substances only by chemical reactions, consist of two or more elements.
- generally properties of compounds are different than that of their component elements.
- specific compound always made up of same elements in same proportion
chemical properties
ability of substance to undergo chemical reactions and form new substances - only observed when substance undergoes chemical change and results in change of chemical composition
law of conservation of mass
total mass of reactants is always equal to total mass of products, quantity of matter is unchanged
Democritus
ancient philosopher, suggested existence of atoms, believed they were indivisible and indetructible
Dalton’s atomic theory main points(5)
1) Everything is composed of atoms, which are the indivisible building blocks of matter and cannot be destroyed
2) all Atoms of an element are identical
3) the Atoms of different elements vary in size and mass
4)compounds are produced through different whole-number combination of atoms
5)chemical reactions results in rearrangement of atoms in the reactant and product compounds
Cathode ray tube
sealed gas tube with near vacuum with two electrodes, when voltage is applied accross them a cathode ray beam occurs
cathode rays
stream of electrons travelling from one end of cathode ray to another
JJ Thomson’s experiemnt
studied cathode ray tubes, believed particles (electrons) must be negative, he said they must be part of all atoms
what was JJ Thomson’s atom model
plum pudding, which was like a cloudy positive particle with negative electrons in it
Milikan’s oil drop experiment
measured charge of electron by having an electric field between metal plates, and speed at which oil drops fell in different voltages helped him figure out the charge of an electron
Rutherford
proved thomson’s model incorrect, used gold foil experiment to show existence of protons and the atomic nucleus
Gold Foil Experiment
used beam of positively charged alpha particles(2 protons and 2 neutrons) and shot at very thing piece of gold foil, studied scattering of particles using screen behind foil, he found that the particles rarely were deflected, meaning the positive bodies within the gold atoms in the foil (neuclei) must be really small for them to be hit, most alpha particles passed through gold foil, showing how much of atom must be empty space.
conclusions from golf foil experiment(2)
- volume occupied by atom must consist of large amount of empty space
- small, relatively heavy, positively charged body (nucleus) must be at the center of every atom
Bohr’s atomic model
said electrons traveled in orbits around nucleus, and that chemical properties were determined by the number of electrons in the outer orbits
chadwik
discovered neutrons with oscilloscope, found they were slightly heavier than protons and had neutral charge
purpose of neutrons
to help reduce repulsion between protons to stabilize atom’s nucleus
quarks
composes protons and neutrons, held together by color force
what is the strong force a byproduct of
the color force
how are protons and neutrons held together
the strong force (gluons)
what is the mass of a neutron/proton (roughly) ?
1.97*10^-24 grams
proton
positively charged subatomic particle forming part of nucleus of an atom, determines atomic number of an element
neutron
subatomic particle forming part of nucleus, no charge
mass of an electron
weigh only 9.11*10^28 grams, usually negligible
atomic mass
average masses of isotopes based on their abundance
Atomic number
number of protons in an element
mass number
number of protons + number of neutrons
atomic mass unit
1/12th mass of carbon- 12 atom?
mendeleev’s periodic table
ordered in terms of relative mass, realized properties of elements related to mass in “periodic” way, arranged them so properties fell together
moseley
discovered that energy of x-rays got larger with each element, proposed it was function of positive charge in nucleus, rearranged periodic table to atomic number instead of mass
periodic law
states properties of elements recur in systematic way when elements are arranged in order of increasing atomic number
horizontal rows in periodic table
periods
vertical rows in periodic table
groups
how many periods are there in the periodic table
7
groups/famlies
arranged so elements in groups have same number of valence electrons
valence electrons
electrons in outer most shell, that can be gained or lost in chemical reaction
metals
elements that have high electrical conductivity, high luster when clean
non-metals
elements that are poor conductors of electricity and are non-lustous when clean
metalloids
intermediate properties between those of metals and nonmetals
alkali metals
group 1 (IA) of periodic table, shiny, soft, highly reactive metals,
Alkali earth metals
belong to group 2 (llA)
alkali earth metals are shiny, silvery white, low density, somewhat reactive
general groups in A type elements
metals, non-metals, metalloids
transition metals
group B elements, are high density, hard, high melting/boiling points
isosagens
belong to group 13 (lllA)
tetragens
elements that belong to group 14 (lV) of periodic table
Pnictogens
group 15 (VA)
Chalcogens
group 16 (VlA)
Halogens
Group 17 (VllA) all nonmetals, highly reactive
Noble Gases
group 18 (VlllA) all odorless, colorless, and nonmetals
types of inner transition metals
lanthanides and actinides
lanthanides
period 6, atomic numbers 57-71, known as rare earth metals
Actinides
period 7, all radioactive, atomic numbers 89-103,
representative elements
elements within groups (lA, llA, lllA, lVA, VA, VlA, VllA, VlllA) - all group A elements
who discovered isotopes
Francis Aston discovered that there were three types of hydrogen atoms, called them isotopes
isotopes
atoms of same elements with different numbers of neutrons, isotopes still have very similar physical properties
half-life
time it takes for half of a sample of an isotope to decay
radiocarbon dating
using how much Carbon 14 has deteriorated in an object to tell how old it is
radioactive isotopes
isotopes that throw off radiation in an effort to become more stable
Alpha radiation
composed of heavy particles, consisting of two protons and two neutrons
Beta radiation
consists of electrons
gamma radiation
consists of photons
isotopes of carbon
carbon 12(98.9), 13(1.1), 14 (<0.1) decreasingly abundant.
