>>>
1) which substance present in car exhaust does not have an effect
on limestone?
A)carbon monoxide
B)carbon dioxide
C)nitrogen dioxide
D)sulfur dioxide
( i chose c , which is the answer and why? )
<<<
CO
is non-acidic. It needs to be oxidized to CO2 before it can be
hydrolysed to carbonic acid to react with limestone.
>>>
2i) what happens when sodium is burnt in the mixture of
gases?
ii)write the chemical equation for the reaction
<<<
Sodium,
like all reactive metals, much prefer to be in the cationic
oxidized state.
>>> 3)suggest why the air (Argon,nitrogen and oxygen)
is filtered before it is compressed.
4) suggest a reason why the gases are stored under high pressure
<<<
Make your own reasonable
deductions : http://en.wikipedia.org/wiki/Compressed_air
>>> 5) suggest why the percentage composition of the
different gases in air is different for the two countries
<<<
Good question with interfaces
chemistry with geography, economics and industrial sciences. Think
about the sources (eg. industrial) of various gases and how they
might be vary significantly across countries and continents (eg.
highly industrialized versus non-inhabited). Also,
Google-&-Wikipedia is excellent for learning and
research.
>>> 6) is nuclear power a renewable of non-renewable
resource? give a reason for your answer. <<<
Like any General Paper question,
this is debatable (there isn't a simple yes or no answer for this
one), and groups with vested interests on either side will push for
their own agenda. Google "nuclear power renewable"
>>> 7a) decribe, using one suitable example, the
formation of ionic bonds between metallic and non-metallic
elements.
b)Explain why ionic compounds have high boiling points and most
covalent compounds have low boiling
point. <<<
Metal atom loses electron(s) to
form cation. Non metal atom gains electron(s) to form anion.
Electrostatic attraction between oppositely charged ions are
referred to as 'ionic bonds'. These electrostatic attractions
between ions are significantly stronger than the relatively
weaker intermolecular (van der Waals) attractions
between molecules of covalent compounds.
>>> 8)a volume of 1000dm3 of methane is burnt
completely in oxygen.
Calculate the volumes of the gaseous products when
measured
i) above 100 degree Celsius
ii) below 100 degree celsius
(assume that all volumes are measured at the same pressure)
<<<
Apply PV=nRT formula. Question is
incomplete with specific values for specific parameters (eg.
1000dm3 at r.t.p or s.t.p?), so use algebraic variables and leave
them in the answer as necessary.
>>> thanks!!! and can anyone tell me the indicators and
their colours in neutral, acid and alkaline solution? do we need to
know all the indicators? our textbook onli wrote colour of
indicator when it is in acidic and alkaline solution so i don't
know the colour of the neutral solution. thanks a lot!
<<<
Google by thy Sword, Wikipedia be
thy Shield.
http://en.wikipedia.org/wiki/PH_indicator
The
colour of any indicator in neutral solution depends on which pH
(acidic or alkaline environment) you began with, and which
direction you're going with the titration.