chemistry unit 1 Flashcards
what is chemistry?
chemistry is the study of matter, the properties
what is matter?
matter is anything that takes up matter
what is an atom?
smallest building block of matter
what is composition?
types of atoms that are present in
what are the different states?
Gas, Liquid, and Solids
what is a pure substance?
matter that has a fixe
what are intensive properties?
independent of the amount of the substance present
example: color, temperature
what are extensive
dependent of the amount of substance present
example: mass, volume
what are the states?
gas, liquid, solid
what are different types of compositon
element, compound, mixture
what are some characteristics of solids
have a fixed volume and fixed shape
what are some characteristics of liquids
have a fixed volume but their shape can change
what are some characteristics of gases
do not have fixed volume or shape
why can gases be compressed
because the atoms and molecules have a lot of space between them
what is a diatomic element
element that comes in pairs
what are the 7 diatomic elements
hydrogen, nitrogen, oxygen, fluorine, bromine, iodine
what is a mixture
combination of two or more substances
what is a homogenous mixture
composition of the mixture is the same throughout
example: milk, sweet tea
what is a heterogenous mixture?
composition is not uniform throughout
example: cement, fruit cake
what are some separation methods
magnet, decant, filtration, distillation, chromatography
what is a physical change?
does not alter the composition or identity of a substance
examples: ice melting or water boiling
what are chemical reaction?
one substance transforms into another by rearranging the atoms bonded together
what is a chemical change?
alters the composition of the substances
example: rust or fire burning wood
what are the characteristics of the scientific method
make observations, form hypothesis, perform experimentation
what is an observation
descriptions about the characteristics of nature
what is a hypothesis
tentative explanation of a set of observations
what is scientific law
describes how nature behaves
what is a theory?
attempts to explain why a natural phenomenon occurs
who was democritus and what did he do?
philosopher who said that matter said matter had tiny indivisible particles called atoms
who were plato and aristotle and what did they say
Philosophers who said that matter is infinitely divisible
who was robert boyle
- relationship between pressure and air
- first chemist
- helped create the fields of physics and chemistry
who was sir issac newton
- laws of motion and gravity
- believed atoms made up air
who was joseph priestly?
discovered oxygen gas
- english clergyman and scientist
who was john dalton
developed the first atomic theory
- contains 4 postulates
what was dalton’s atomic theory
- ) each element is composed of atoms
- ) all atoms of a given element are identical in mass and other properties, but the atoms of one element are different from the atoms of all other elements
- ) atoms of an element are not changed into atoms of a different element by chemical reactions
- ) compounds are formed when atoms of more than one element combine; a compound has the same relative number and kind of atoms
what is the law of conservation of mass
matter cannot be created or destroyed
what is the law of conservation of matter
mass cannot be created or destroyed
who was antoine lavoiser
- father of modern chemistry
- discovered role of o2 in combustion
what is the law of definite proportions
states all samples of a given compound have the same proportions of their constituent elements
what is the law of multiple proportions
states that elements combine to form compounds in whole number ratios
what did cathode rays show scientists
cathode rays are deflected by electric or magnetic fields in a way that is consistent with a negative electrical charge
who was j.j thompson
believed that the cathode ray was composed of tiny particles with an electrical charge
- discovered the electron
what were thompsons results
determined that the amount of deflection was related to the charge and the mass of the particles
- measure charge to mass ratio of electron
what are the behaviors of charge
- 2 charges
- opposite charge attract
- like charges repel
who was robert milikan
measured the charge of an electron in 1909
And discovered the charge of an electron
what is the mass of an electron
9.10 x 10^-28g
what was the plum pudding model?
early theory of what the atom looks like they said it was a positive sphere with negative electrons inside it
developed by jj thompson
who discovered the three types of radiation
ernest rutherford
what are the three types of radiation
alpha particles, beta particles and
explain rutherford’s gold foil experiment
rutherford shot alpha particles at a thin sheet of gold foil and observed the pattern of scatter of the particles
- some alpha particles were deflected at large angles
what was rutherford’s nuclear theory?
- most of the atoms mass and the positive charge are in the nucleus
- most of the volume is empty space where the electrons are dispersed
- there are as many electrons outside the nucleus as there are protons within the nucleus
what are neutrons
subatomic particle without a charge
- located inside the nucleus
who is sir james chadwick
discovered neutrons
what is the mass of protons and neutrons
1 amu
what is the mass of electrons
0 amu
what is used to identify an element
its atomic number
what makes up the atomic mass
protons and neutrons
which subatomic particles are equal
the number of protons and the number of electrons
what are isotopes
atoms of the same element with different masses due to difference in neutrons
who found isotopes
frederick soddy
what is an ion
when an atoms loses or gains electrons (transfers electrons)
what is a cation
ion with positive charge
loses electrons
what is an anion
ion with a negative charge gains electrons
