science chemistry Flashcards
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what is an atom
they are basic building blocks of matter and contain a central nucleas with protons,neutrons and electrons surrounding it
how is a positive ion formed
it loses electrons
what is an ionic bonding
a strong force between oppositely charged metals
what is metallic bonding
its forces of attraction between oppositely charged to hold the metals together.
when can ionic compounds conduct electricity
when ions can move e.g. in liquids when compounds are dissolved
endothermic-
takes in energy from surroundings e.g. melting
exothermic-
gives out energy to surroundings e.g freezing
reaction profile-
shows chnages of reactants and products during reaction
rate of reaction-
how fast a reaction occurs
example of slow rate of reaction-
rusting
how do you measure the rate of reaction
you measure how quickly reactants are used up or how quickly product is made
two things needed for two particles to react
must collide hard enough or with enough energy
reaction occur faster when
more reactant particles collide with each other
a way to increase the number of colliding particles
increase surface area of a reactant
why do reactions get slower as they progress
there are fewer and fewer reactant particles
what is salt
is an ionic compound produced by neutralisation reaction
what is neuatralisation
an acid that reacts with an alkali or a base to form a salt or water
state symbols
liquid-(L) as-gas-(g) solid-(s) and aqueus(aq)
what is a reversible reaction
its a reaction that can go forwards and backwards
what is dynamic equilibrium
when forwards and reverse procceses occur at same time,resulting in no overall observable change
3 main types of bonds are
metallic
ionic
covalent
why are metals strong
force of attraction between ions and electrons keeps metal together
what is explosion
sudden increase in volume of gas and huge transfer of energy to surroundings
wha is physical changes
changes where no new substances are made
what r chemical changes
changes where 1 or more new substances r made
term flammable-
a substance catches fire easily
reactants
the starting substances used to make products
product
a new substance formed by reactants
gas pressure
the force gas particles exert by hitting walls of the container
how to increase gas pressure
-increase temperautre
-increase the number of articles
-decrease size of container
metals n water-
hydroxide and hydrogen
metals n oxygen-
metal oxides
oxidation?-
a reaction where a substance reacts,combines and gains oxygen
how to protect rust
use a barrir or paint/oil/plastic to prevent air/water
how id rust formed
formed by the corrision of iron and rust
how is gunpowder made
mix pottasium nitrate and powdered charcoal
an exothermeric reaction e.g.
combustion
an endothermic reaction e..g
thermal decomposition
what is displacement reaction
a reaction where a more reactive metal displaces a less reactive metal
what is native state
when a metal is found in the earth as an elemant
what is ore-
rock that contains enough mineral to be worht mining
a way to extract iron-
heating with carbon
whta is electrolysis
a way to extract reactive metal using electricity
an example reaction which can electrolysis
aluminium pottasium
