Studied by 2 peopleWhat are the three states of matter?
solid
liquid
gas
What is a solid?
the particles are arranged and close together
What is a liquid?
the particles are randomly arranged and close together
What is a gas?
the particles are randomly arranged and far apart
What is a chemical change?
what is created is chemically different to what is reacted
What is a physical change?
changing in state eg. melting
What is a limitations?
the attraction and spaces between particles
What did John Dalton do?
atoms make up all substances
What did Tomson do?
the plum pudding model
What did Rutherford do?
that atoms have a nucleus and the proton
What did Bohr do?
electrons are in shells
What is an atom?
negatively charged electrons surrounding a positive nucleus
What is smaller molecules or atoms?
atoms as they make up molecules
What is the relative charge and mass of a proton?
charge +1
mass 1
What is the relative charge and mass of a neutron?
charge 0
mass 1
What is the relative charge and mass of an electron?
charge -1
mass 1/1836
What is an atomic number?
number of protons (electrons)
What is an isotope?
an element with different neutrons but the same protons
What is the mass number?
protons + neutrons
What is an ion?
an atom with a charge
How do you find the number of protons?
the same as the atomic number
How do you find the number of neutrons?
mass number - atomic number
How do you find the number of electrons?
number of protons
What is a pure substance?
an element or compound that melts/boils at specific temperatures
What is relative formula mass?
relative atomic masses added together
What is empirical formula?
the simplest ratio of the numbers
What is a formulation?
something (a mixture) which has been created to be a useful product eg. medicines
What is filtration?
filtering a solution to leave you with a precipitate
What is crystallisation?
separating a salt from a solution by evaporating the water
What is simple distillation?
separating a pure liquid from a solution by heating the mixture at the specific boiling points
What is fractional distillation?
normally done with oil by heating the mixture at different temperatures and condensing the vapour produced
What is chromatography?
separates mixtures and uses mobile and stationary phases
What is paper chromatography?
the mobile phase is the solvent and the stationary phase is the paper
What is TLC (thin layer chromatography)?
the mobile phase is the solvent and the stationary phase is an inert substance on a non-reactive surface
what is the Rf value?
distance moved by substance ÷ distance moved by solvent
What is gas chromatography?
the stationary phase is the liquid and the mobile phase is the inert gas carrier
What is a metal?
a reactive element that creates positive ions
What is a non-metal?
a reactive element that creates negative ions
How is the periodic tables organised?
in order of atomic number and elements in the same group have the same amount of electrons
What is the chemical bonds in ionic compounds?
when a metal and non-metal bonds and is connected with high forces and giant ionic lattices
What is the chemical bonds in simple molecules?
when molecules are covalently bonded by sharing electrons are normally gases or liquids
What is the chemical bonds in giant covalent structures?
solids with high melting points
What is the chemical bonds in polymers?
are connected by string covalent bonds and intermolecular forces so is solid at room temperature
What is the chemical bonds in metals?
giant structures and shared delocalised electrons with high melting and boiling points
What is a covalent bond?
electrostatic attractions between shared electrons
What is an ionic bond?
electrostatic attractions between charged ions
What is metallic bond?
electrostatic attractions between positive metal ions and delocalised electrons
What do dot and cross diagrams represent?
forming of ionic compounds but cannot represent the 3D arrangements
What is the arrangements of electrons in shells?
2,8,8
What was Mendeleev’s arrangment?
in order of atomic mass but left some missing for undiscovered elements
What is the structure of diamond?
each carbon is then connected covalently to four other carbon
What is the structure of graphite?
graphite is soft as each carbon is bonded to three other carbon atoms and they are in layers which can slide
What is the structure of fullerene?
made up of rings of five to seven carbon atoms
What is the structure of graphene?
one layer of graphite
What is energy transfer?
to - boiling,melting
from - freezing,condensing
What is the relative strength of chemical bonds?
both covalent and ionic bonds are extremely strong
What is intermolecular forces?
are weak so have low melting and boiling points
How big are nano-particles?
1x10-7 m
What are the features of nano-particles?
high surface area to volume ratio
What are the risks of using nano-particles?
there are unknown dangers of how our cells react
Why do elements form ions?
they form ions to have a full outer shell of electrons
What is the state symbol (s)?
solid
What is the state symbol (aq)?
aqueous
What is the state symbol (l)?
liquid
What is the state symbol (g)?
gas
What is a mole?
an amount of a substance
What is Avogadros constant?
6.02 x 10(23)
What is the formula for mol?
What is the law of conservation of mass?
mass of reactants = mass of products
What is an exothermic reaction?
when the temperature of the surroundings increase
What is an endothermic reaction?
takes energy from the surroundings making the tempereture around decrease
What is the activation energy?
the minimum amount of energy needed for a reaction
Exothermic reaction profile
Endothermic reaction profile
What is oxidation?
loss of electrons
What is reduction?
gain of electrons
What ions are released when acids dissolve in water?
H +
What ions are released when alkalis dissolve in water?
OH -
What is a neutralisation?
an alkali reacting with an acid to create water plus salt
What does Hydrochloric acid produce?
chlorides
What does Nitric acid produce?
nitrates
What does sulfuric acid produce?
sulfates
What are three examples of strong acids?
Hydrochloric acid
nitric acid
sulfuric acid
What are three examples of weak acids?
Ethanoic acid
citric acid
carbonic acid
What is the pH for neutral?
7
What is the pHs for acid?
< 7
What are the pHs for alkaline?
7
What are three types of universal indicator?
Litmus paper (red&blue)
Phenolphthalein
Methyl orange
Positive ions
cations
Negative ions
anions
What electrode are cations attracted to?
anode (positive)
What electrode are anions attracted to?
cathode (negative)
What is produced at the cathode?
hydrogen unless there is a metal less reactive
What is produced at the anode?
oxygen unless there is a halide ion
What are the halide ions?
Cl-
Br-
I -
Anode
loss of electrons
Cathode
gain of electrons
What are non-inert electrodes used for?
reactive products and purifications
Note
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