1 to 13 is solved. please start from q14 onwards.
tytyyyy
1)portion of acidified potassium manganate VII solution added
into sample of solution X . X decolourised the potassium
manganate solution . resulting solution was brown
An orangic solvent Y added to mixture above and left to stand.
colourless layer of Y turned violent . What conclusion can be
drawn about X ?
a) it is a reducing agent and contain iodide ions
b) it is a reducing agent and contain bromide ions.
2) sample of waste gas passed ino alkaline solution of a
compound called pyrograllol . remaining gas burns in air .
gas
removed
gas remained
1)co2
h2
2)NO2
o2
3) 2 experiment setup to demo diffusion of gases are done. gases
in each porous pot are N2 and O2 . In the first exp. gas intro into
beaker is CO2 while in the second and Seperate expt , H2 is
introduced.
*diagram shows a porous pot in a beaker with the gas
introduced(CO2/H2) connected to a U - shaped tube with the side
connected to the porous pot and water lvl of P and the other end
exposed to atmpsphere pressure in which the water level is labelled
Q .
wht changes can be seen in water lvl P and Q in both expt ?
4) Thallium is a metallic elemetn and exits in to isotopic form
which have mass number 203 and 205 respectivel, 10g of thallium
reacts with excess chlorine to give 15.2g of compound ticl3 . based
on the data. calculate Mr or thallium
a) 203.4
b)203.6
c)204.5
d)204.8
my working
10/x=15.2/x+106.5
15.2x=10x+106.5
5.2x= 106.5
x=204.8
but i keep thinking need to do
sth with the isotope ?
5)Y is a compound with valencey of 5.
hence, the formula of compound formed between calcium and Y is
?
a) CaY
b) CaY2
c) Ca2Y3
d) Ca3Y2
6) element X has electronic structure 2,8,5 and element Y has
electronic strucutre 2,8,7 . what is the likely formula of a
compound containing X and Y only?
a) XY3
b)X3Y
c) X5Y7
d) X7Y5
For qn 5 and 6 is there a quik
method instead of drawing it out ? ?
7) Metal Z and its compound undergo following
reactions
1 X+2Hcl -> ZCl2 + h2
2 ZCo3 -> ZO + CO2
3 ZO+ CO -> Z + CO2
Metal Z could be
calcium
magnesium
copper
zinc
from the above information given i could only be sure that it
isnt copper.
for the breakdown of carbonate i
cant take away calcium as only sodium and potassium canot be broken
down by heat from what i have learn. for the CO reaction i nvr
learn b4.
8) X has proton num of 9 (2,7)
Y has proton num of 7 (2,5)
the compound formed by X and Y is
a) total num of 6 shared electrons
b) molecular forumula XY3
c) molecular formula X5Y
9) Which of the folloowing has the most number of electron ?
a)magnesium ion
b) molecular of HCL
10)
11) Z is a non-metal . Oxide of Z has a high melting point. Z is
probably
a) carbon
b) silicon
c) posophorus
d) sulfur .
is silicon the answer as it has the biggest negative oxidation
state? eg. 2,8,4 . 4+/4- ? ?
12) W has a gaint covalent structure, which 1 of the following
description is true ?
a) constituent particles in W are atoms
b) W exsists as discrete molecules
can sum1 explain why answer is A ?
13) which property of Nitrogen gas explained by the covelent
bond in its molecules ?
a) acidity of Nitrogen oxides
b) low reactivity of
nitrogen
c) low b.p
i choose c . why canot ?
x.x
14) 4dm3 of co2 contains
a) 2.4x10^24 atoms
b)3x10^24 atoms
c)10^23 atoms
d) 1.2x10^23 atoms
ans sheet is B , but i choose C ,
i think ans sheet wrong, can sum1 x2 check ?
15) num. of atoms present in 34g of NH3 is
a) 1.2x10^24
b) 4.8x10^24
ans sheet says B but i choose A
. i think ans sheet is wrong, can sum1 check too ?
16) Zinc nitrate decomposes on strong heating acc. to eqn
below.
2Zn(NO3)2.6H20 -> ZnO(s)+ 4NO2(g) + O2(g) + 6H20 (g)
14.85 gram of crystal heated strong, what is total vol of gas
obtained ?
a) 3 dm3
b) 6.6dm3
c)1.2dm3
d) 7.8dm3
ans sheet say A . but i choose B
. can sum1 x2 check answer? i think ans sheet wrong
-.-
17) which of the following has the same mass as 6x10^23 atoms of
copper ?
a) 6x10^23 atoms of iodine.
b) 12x10^23 atoms of magnesium
c) 12x10^23 of sulfur
d)24x10^23 atoms of nitrogen
i wrote C but ans is A . cant
figure out.
18) 10g of CaCO3 just neutralises 100cm3 of hcl acc. to eqn
below
CaCO3 + 2HCL - > CaCl2+H2O + CO2
what is conc of HCL ?
a)1mol/dm3
b) 2mol/dm3
ans is A but i wrote B .
why sia , suspect ans wrong
19) sample of N2 contains same num of atoms as found in 4g of
CH4 .. what is mass of N2 gas ?
a) 7g
b) 17.5g
ans sheet is b but i choose a
!
20) which of the following substances has the most number of
atoms ?
a) 10g nitrogen
b)10g magnesium
since qn nvr say gas or what.. i
assume is diatomic gas.
but ans sheet is a . while my
answer is b
21) 6,94g of mixture wwith BaCO3
and CaCO3 is heated. after removing CO2 , 4.74g of mixture with CaO
and BaO is obtained. Orginal weight of BaCO3 is. .. ..
a) 1.97g
b)3.94g
c) 5.91g
d)3.06g
seriously dunoe how to do this 1 .
22)gas contains 46.2% of carbon and 53.8% of nitrogen . under
r.t.p vol and weight is 6dm3 and 13g . the gas is
a) C2N2
b) CN
ans sheet say is A . i chosoe B .
cause i got ratio of 1:1
23)
24) m Fe2+(aq) +
n H+ (aq) + MnO4-(aq) ->
Mn2+ (aq) + p Fe3+ (aq) +
q H2O(l)
what is m,n,p,q
a) 2, 4,2, 2
b)3,6,3,3
c)4,8,4,4
d)5,8,5,4