TYS 'O' LVL chem questions

last SG · 2008-10-15T00:35:24+00:00

relax relax.just do ur paper, mind ur own business.don look left right centre, just focus.

gunner77 SG

2006 - 5b

both hydrogen and helium have been used to fill balloons. Hydrogn is more reactive and less safe to use.

use the electronic structure of the atoms of these two elements to explain why hydrogen is more reactive than helium. (3marks)

2006 - 5c

Aluminium is an element in group 3 of the periodic table. Use your knowledge of electronic structure to explain why aluminium is a metal. (3marks)

anyone can help me?

crimsontactics SG

Helium is a noble gas, noble gas have no charge and are stable and unreactive

Hydrogen has a plus one charge, it needs one more electron to achieve the noble gas structure, thus it is more reactive than helium as there are transfer of electrons happening.

crimsontactics SG

2006 - 5b

both hydrogen and helium have been used to fill balloons. Hydrogn is more reactive and less safe to use.

use the electronic structure of the atoms of these two elements to explain why hydrogen is more reactive than helium. (3marks)

2006 - 5c

Aluminium is an element in group 3 of the periodic table. Use your knowledge of electronic structure to explain why aluminium is a metal. (3marks)

anyone can help me?

It has three valence electrons, causing it to give out rather than take in electron to form an ion.

Maith SG

aluminium has 3 outer electrons thus it will give away 3 electrons to form a ionic bond with a non-metal. And metals are always the one that gives away electrons..

lol,2 more days to practical! ):

gunner77 SG

It has three valence electrons, causing it to give out rather than take in electron to form an ion.

but like tat answer will give u full 3 marks?

Ahm97sic SG

Hi Gunner,

tin tin is online, perhaps you can ask him now.

Regards,

ahm97sic

gunner77 SG

anybody can help me answer can liao

tinuviel07 SG

gunner dowan me liao... and tin tin is a she thanks

gunner77 SG

gunner dowan me liao... and tin tin is a she thanks

HUH !!

U ARE A GAL ! wah seh i thought u boy

no la i want u

pls help me :(

tinuviel07 SG

lol.. =.="

both hydrogen and helium have been used to fill balloons. Hydrogn is more reactive and less safe to use.

use the electronic structure of the atoms of these two elements to explain why hydrogen is more reactive than helium. (3marks)

When elements have stable electronic configurations, they are very unreactive as they have a fully-filled outer shell. Hydrogen has electronic configuration 1 and hence it will undergo bonding with another element to form a compound to achieve stable electronic configuration.

Helium on the other hand, has 2 electrons in the outershell, hence its outershell is completely filled, making it very stable and unreactive.

gunner77 SG

then the part B leh

crimsontactics SG

lol.. =.="

both hydrogen and helium have been used to fill balloons. Hydrogn is more reactive and less safe to use.

use the electronic structure of the atoms of these two elements to explain why hydrogen is more reactive than helium. (3marks)

Helium on the other hand, has 2 electrons in the outershell, hence its outershell is completely filled, making it very stable and unreactive.

I think it would much easiler to just remember helium as a noble gas. Noble gases are unreactive and stable.

tinuviel07 SG

yes it's true that noble gases are unreactive but the question asked why.. or did i read it wrongly?

crimsontactics SG

but like tat answer will give u full 3 marks?

Hmm, i think its this way,

1. Al has 3 valence electrons

2. Causing it to give electrons rather than take

3. To form a positive ion ( by maith )

crimsontactics SG

yes it's true that noble gases are unreactive but the question asked why.. or did i read it wrongly?

Your answer is correct. It's just that i fill that by writing the noble gases thing will be more time-saving as it requires lesser words.

gunner77 SG

ohh thanks everyone !

tin tin help me with maths

i post the question liao thanks very very much!

gunner77 SG

solid D is a speckled green and white.

the green particles dissolve in water but the white particles do not.

is solid D a compound, element or mixture?

the answer is mixture but i dont understand why?

there is only 2 particles, shouldn't it be compound?

tinuviel07 SG

i put it crudely ok? haha..

if the whole thing is compound, the whole thing should dissolve in water or the whole thing should not dissolve in water ma.. means there's two separate parts behaving differently in water.. means mixture lor.. cause two separate things together..

if like say you put NaCl in water.. the whole thing dissolve right? won't be one part dissolve one part don't..

but if you have say NaCl and BaSO4 (insoluble in water), then the NaCl will dissolve but the BaSO4 won't and this is a mixture cause they behave differently

gunner77 SG

ohh !

icic. hmm now i understand.

thanks! one more question.

an ore contains 10% by mass of the minera, wolframite

wolframite contains tungsten,W and has the formula (FeMn)WO4

(i) calculate the mass of wolframite in 10 tonnes if the ore.

(II) calculate the mass of tungstenin 10 tonnes of the ore.

[ relative atomic masses: A; O, 16; Mn, 55; Fe 56; W, 184 ]

tinuviel07 SG

ohh !

icic. hmm now i understand.

thanks! one more question.

an ore contains 10% by mass of the minera, wolframite

wolframite contains tungsten,W and has the formula (FeMn)WO4

(i) calculate the mass of wolframite in 10 tonnes if the ore.

(II) calculate the mass of tungstenin 10 tonnes of the ore.

[ relative atomic masses: A; O, 16; Mn, 55; Fe 56; W, 184 ]

who the hell give such a name.. grr

Mass of wolf = 10% x 10tonnes = XXX

Mass of tungsten = (Ar of Tungsten / Mr of wolf) x ( XXX )

remember to change tonnes to grams