All of year 9 Flashcards
What are the 3 states of matter
liquid
solid
gas
what does each sate of matter depend on
how strong the forces of attraction are between the particles of the material
descirbe the arrangement in solids and why
very regular because of the strong forces of attraction holding them together
describe the movement of solid particles
they don’t move but do vibrate about a fixed point whilst keeping a definite shape and volume
what happens when materials are heated
the particles vibrate/move more gaining energy causing the material to expand
describe the arrangement and movement of liquids
weak forces of attraction cuase the particles to be random and free to move over each other and fill the bottom of the container
desribe the arrangement of gas particles
very weak forces allow the particles to be free to move and be far apart filling any container
What happens when gases are heated
they either expand or the pressure is increased
what is the process where a solid becomes liquid
melting
what is the process where a liquid becomes a solid
freezing
what is the process where a liquid becomes a gas
evaporating
what is the process where a gas becomes a liquid
condensing
what is the process where a solid becomes a gas
subliming
what is diffusion
the gradual movement of gas or liquid particles from places where there are lots to places where there are fewer
In a diffusion experiment with ammonia and hyrogen chloride why is the ring of ammonium chloride not in the center
becuase the hydrogen chloride particles are denser than the ammonium particles - they take longer to move
what is a solution
a mixture of solvent and solute that does not seperate out
what is a solute
the substance being dissolved
what is a solvent
the liquid the solute dissolves into
what is a saturated solution
a solution where the maximum amount of solute has been dissolved
what is solubility
the measure of how much solute will dissolve in 100g of solvent
how do you calculate solubility
(mass of solid / mass of water removed) x 100
How can you investigate how temperture affects solubility
- weigh empty evaporating basin
- pour some solution in basin
- re-weigh basin
- heat with bunsen burner
- re-weigh pure substance once water evaportated
define isotope
isotopes are different atomic forms of the same element, which have the same number of protons but a different number of neutrons
what does the atomic number of an element tell you
how many protons
how can you find out the group number of an element
the number of electrons on the outer shell
how can you find out the period of an element
the number of occupied shells
what is an element
an element consists of only one atom
what is a compound
compounds are chemically boned elements (two or more)
what is a mixture
mixtures are easily seperated: there is no chemical bond
how can you tell if something is a pure substance
because it will have a speecific, sharp melting and boiling point
What is filtration used for
to seperate an insoluable solid from a liquid
what is crystallisation used for
to seperate a soluable solid from a solution
what do you need to perform filtration
beaker
funnel
filter paper
what is the mixture that stays in the filter paper call
the residue
how does crystallisation work
- pour mixture into evapourating dish
- heat solution ~ water will evapourate
- once water evaporated leave dish to cool and dry
why does chromatography work when seperating mixtures
becuase dyes in the mixture move up the paper at different rates
how do you preform chromotagraphy
- draw base line wiht pencil
- add spots of ink to baseline
- loosely roll paper and put in beaker with some water (ensure the baseline is above water level)
- once dyes have spread take out to dry
how do you calculate the Rf value
distance travelled by solute / distance traveled by solvent
when is simple distillation used
to seperate out solutions
when is fractional distillation used
to seperate out a mixture of liquids (with similar boiling points)
how does simple distillation work
- solution is heated
- part of solution with lowest BP evapourates
- vapour is cooled and condenses and collected in beaker
- rest of solution is left in falsk
What do you need to conduct distillation
flask
bung
thermometer
beaker
liebig condenser with water jacket
bunsun buner
tripod
what is the relative charge of a proton
+1
what is the relative charge of a neutron
0
what is the relative charge of an electron
-1
What is the relative mass of a proton
1
What is the relative mass of a neutron
1
What is the relative mass of an electron
0.0005
what does the mass number of an element tell you
how many protons and neutrons there are
how do you calculate the relative atomic mass of isotopes
((mass number x percentage) + (mass number x percentage)) / 100
Why are the elements lower down in the group most reactive
becuase the outermost electron is further from the nucleus so the attraction is less
What is a negative ion called
an anion
what is a positive ion called
a cation
what is an ion
an atom with a charge
describe ionic bonding
- metal + non-metal react to get complete outer shell
- metal loses electron(s) forming a cation
- non-metal gains the electron(s) forming an anion
- oppositely charged ions are strongly attracted by ellectrostatic forces causing the bond
define ionic bonding
the electrostatic forces of attraction between two oppositely charged ions
why do ionic compounds have high MP and BP
becuase the a lot of energy is needed to overcome the strong attraction
can ionic compounds conduct electricity
yes but only when molton or dissolved becuase the ions have to be free to maove and carry the charge
How are metals held together
by metallic bonding
describe a metallic bond
a giant structure of positive metal ions surrounded by a sea of delocalised electrons
what does this diagram show
metallic bonding
define metallic bonding
the strong electrostatic forces of attraction between metal ions and delocalised electrons
why can metals conduct electricity
because the delocalised electrons can move to carry a charge
why are metals malleable and ductile
becuase the layers of metal ions can slide as the atoms are all the same size
what is the state symbol for solid
(s)
what is the state symbol for liquid
(l)
what is the state symbol for gas
(g)
what is the state symbol for dissolved in water (aqueous)
(aq)
what are metal ores
reactive metals found in the earths crust that have enough metal to be extracted from their ore
what is the reactivity series
Potassium
Sodium
Calcium
Magnesium
Aluminium
Carbon
Zinc
Iron
Tin
Lead
Hydrogen
Copper
Silver
Gold
how are metals more reactive than carbon extracted
using electrolysis
what is the word equation for rusting
iron + oxygen + water –> hydrated iron(III) oxide
What are the the two methods to prevent rusting
barrier methods
sacrificial methods
What are barrier methods to pevent rusting
painting
oiling
what are sacrificial methods to prevent rusting
galvanising
what is galvanising
when a coating of zinc is sprayed onto an object so that the whole object will not rust
define covalent bonding
the electrostatic forces of attraction between the shared pair of electrons and the nuclei of the bonding atoms
describe covalent bonding
- non-metals react together to get full outer shell
- they share electrons
what are intermolecular forces
simple covalent substances have intermoleccular forces, these are the forces between the covalent molecules themselves
if a covalent molecule has a high melting point what are the intermolecular forces like
strong
if a covalent molecule has a low melting point what are the intermolecular forces like
weak
do covalent molecules conduct electricity
no becuase there are no free moving charged particles
what are the three most important giant covalent structures
diamond
graphite
sand
what is diamond made up of
carbon
what is graphite made up of
carbon
what is sand made up of
silicon and oxygen
describe graphites intermolecular forces
weak but still present
why can you write with graphite
becuase the weak intermolecular forces between the layers
Why does graphite have a slippery feel
because weak intermolecular forces hold the layers of carbon atoms together, therefore making the layers able to slide and graphite has delocalised electrons as well so it can conduct
why do giant molecular structures have high boiling and melting points
because they require a lot of energy to overcome the strong covalent bonds
What is the structure of diamond like
tetrahedral
what is the structure of graphite like
hexagonal layers
Why is diamond hard
because the tetrahedral stucture allow external forces to be spread throughout the lattice and the forces of attraction are stong so they require a lot of energy to overcome
why is graphite soft
because weak forces between layers allow to slide easily
why does graphite conduct electricity
there are delocalised electrons between the layers
