structured questions Flashcards
why does molten ___ (e.g. iron) do not react with the incoming air
as hot air rises, it will not come in contact with the heavy molten iron which will sink to the bottom
why are the elements in group 0 inert?
it has a full valence shell that does not want to lose or gain electrons hence it is not reactive
what are the 2 main elements present in a petroleum fraction
carbon and hydrogen
what happens to the particles when solid is heated
they gain energy and move further apart
arrangement of particles during condensation
particles become closer together and move more easily
particles - evaporation of water
particles move further apart
orderliness of particles in both water and water vapour remains unchanged
why farmers should not add excessive amount of calcium oxide to soil
the soil will become too alkaline and will not be suitable for plant growth
what are the 3 ways to test the purity
boiling point
melting point
paper chromatography
define diatomic
refers to two atoms chemically bonded together to form a molecule
in which conversion do water molecules lose speed
ice to steam or steam to ice
steam to ice
write an ionic equation to show what it meant by the term neutralisation
OH-n (aq) + H+ (aq) —–> H2O (l)
explain why the water level in the test tube has risen after one week
oxygen in the test tube is used up during rusting
state a method by which the precipitate can e separated
filtration
explain why a measuring cylinder is not suitable for making this measurement
as it can only measure up to 0.5cm3
state two physical properties of sodium that are typical of group 1
- they are soft and cut easily with a knife
- low densities
which 3 metals are unreactive to acid
copper
silver
gold
explain why carbon monoxide is formed in car engine
it is produced by the incomplete combustion of fossil fuels in the car engines
explain why cracking method is important in oil industry
to produce smaller and more useful molecules
describe how fractional distillation separates paraffin from petroleum
fractional distillation
petroleum is heated in a furnace into a vapour
it then rise up in the column and begins to cool and condense
fractions with smaller hydrocarbons have lower boiling points, cools and condenses first
collected at the top
state how nitrogen dioxide acts as an atmospheric pollutant
acidic oxide dissolve in water to produce acid rain
killing aquatic life
what is a poisonous gas
carbon monoxide
which gas is colourless and odourless
carbon monoxide
do u have to put the Mr units?
no need
what is the physical state of glucose in room temperature
solid
explain why is it a good practise to repeat titration several times
to ensure that consistent readings are obtained so that the result will be reliable
describe a test that could be carried out on the soil sample to show that the soil had changed from acidic to alkaline
add universal indicator
observation before: acidic soil will turn universal indicator orange/ yellow
observation after: alkaline soil will turn universal indicator blue
what are the advantages of recycling metal
to reduce the usage of landfills
conserve earth’s finite natural resources
why recycle metal
as metals are in high demand as they are limited resources
define alloy
is a mixture of metals with other elements
fractional column use for
to separate the liquids
ammonium hydroxide
NH4OH
brass is made up of
copper and zinc
bronze is made up of
copper and tin
steel is made up of
iron and carbon
stainless steel is made up of
iron and carbon and chromium
cations
metals from positively charged ions
anions
non metals from negatively charged ions
glass beads
provide large surface area so that vapour can undergo repeated condensation and boiling
