Topics 1.1 and 1.2 Flashcards
elements
primary constituent of matter that cannot be broken down into simpler substances
compounds
atoms of different elements chemically bonded together in a fixed ratio
mixtures
more than one elemnt or compound in no fixed ratio, not chemically bonded thus can be seperated by physical methods
how do you carry out filtration
filtration is used to seperate a solid from a liquid, or a soluble solid from an insoluble solid by dissolve them in a liquid beforehand
you need a conical flask, a filter paper and a filter funnel where the solid which remains in the filter paper is called the residue, and whatever passes through the filter paper into the conical flask is the filtrate
how do you carry out evaporation
used to seperate a solid from a liquid
where you heat the mixture and the liquid will evaporate, the solid remains
how do you carry out distillation
used to seperate two liquids with different boiling points, the liquid with the lowest boiling point evaporates first and will pass through a condenser where it is turned back into a liquid and collected at the opposite end of the distillator
how do you carry out chromotography
seperates componentss of a mixture, you must draw a baseline on the filter paper using a pencil, and place your mixture on the baseline, you then place you filter paper in a solvent which musnt reach the baseline. your different mixtures will move along the filter paper might need a locating agent to view, and you can then calaculate the rf value by dividing the total distance the individual component traveled from the baseline by the total distance traveled by the solvent
what is meant by homogeneous
A type of mixture that a uniform composition and no visible phases or boundaries
meaning that the components of the mixture are equally distributed and in the same state, making the composition the same throughout the mixture
what is meant by heterogeneous
A type of mixture with a non-uniform composition with visible phases or boundaries.
kinetic molecular theory
a model to explain physical properties of matter (solid, liquids and gases) and changes of state
what are the endothermic changes of state
melting, boiling, sublimation
energy is taken in to break the bonds and change state
what are the exothermic changes of state
freezing, condensation, deposition
energy is released into the surroundings
what is sublimation
solid to gas
what is deposition
gas to solid
formula to convert celsius to kelvin
celsius + 273 =kelvin
what is temperature in kelvin an average measure of
kinetic energy of particles
describe an atoms nucleus
positvely charged dense nucleus composed of neutrons and protons
where do negatively charged electrons occupy
occupy the space around a nucleus
in nucleur symbol notation what does A and Z stand for
A= mass number
Z= atomic number
how do you calculate number of protons neutrons and electrons from A and Z
Z= number of protons= number of electrons (in an atom)
number of neutrons= A-Z
what are the masses of proton neutron and electron
proton= 1
neutron=1
electron= negligible
what are the charges of proton neutron and electron
proton= +1
neutron= 0
electron= -1
isotopes
atoms of the same element with different number of neutrons
how do calculate relative atomic masses
mass number of each isootope is multiplied by its abundance and all of them are added together
they are then divided by 100
can there be differences in physical properties of isotopes
yes
why are mass spectra used
to determine the realtive atomic masses of isotopes from their isotipic compositions
