₦airaland Forum

[quote author=t.boy007]B[/quote]Explain the reasons to others.....

joseboy199: correct...it helps in osmoregulation...balancing of water and mineral salt in d body....
diz z wat d thread z al abt askin que,gvn que...2 make it interactive.4 a beta result...tenx bro

Thats tru boss

Which of the following gases will have the lowest rate of diffusion under the same conditions?

A.Argon
B.Chlorine
C.Nitrogen
D.Oxygen

joseboy199: He z ryt bro....

How is Q posibu wtout current please...cos I knw we are lukin for current and we were given time.....xo xplain mor beta

N2 + 3H2 <===> 2NH3 Dh = -92kjmol^-1

Whats the effect of increasing the temperature of the system

A.The forward reaction will be favoured
B..Backward reaction will be favoured
C.The will be no effect
D.Both forward and backward reaction will be favoured.

Kunlexic: The organ in man that perform similar function as the contractile vacuole of Amoeba is a.liver b.kidney c.lung d.skin e.bladder

B kidney...Amoeba uses ontractile vacuole for excretion and man use kidney for excretion...

.

Kunlexic: I=?,m=0.16g,t=15*60secs=900secs
Cu^2+ + 2e-=Cu, 2F liberates 1 mole of copper,2*96500=63.5g
then 0.16g of Cu will be liberated by 193000*0.16/63.5=486coulombs of electricity
from Q=it,where Q=486coulombs,time=900secs,then
486=i*900,i=486/900=0.54A.

Lolzz...aw dd u get coulombs of electricity without Current please....abi u fit cuk ric wtout heat ni........rmemba Q = It.....thats y I always tel u to gv optns....ya approach to the question invisibly is wrong...

.

buzyguy: Hw many atoms r there in 2moles of hydrogen moleculez? Itz calculatn o

moles = no of particles/6.02 * 10^23

2 = particles/6.02 * 10^23
particles = 2 * 6.02 * 10^23

particles = 12.04 * 10^23

or 1.204 * 10^23

Give options next time please...

Kunlexic: 4rm d 1st law:m¤Q but Q=it,.'.m=KIt.
The mass of d element discharge depends on i.the magnitude of current dat is passed ii.the time taken 4 d current to pass
when a graph of mass(kg) is plotted againdt the time in sec or currunt in ampere,a straight line grahj will be obtained.
4rm d 2nd law,we have dat 1e-=1F=96500C E.g CuSO4 and AgNO3 are different electrolytes wen d same qty of electricity is passed 2ru it CuSO4--Cu^2+ SO4^2-
Cu^2+ + 2e-=Cu,2e-=2F=1 mol of Cu
from AgNO3,Ag+ + e-=Ag,here 1e-=1F=1 mol of Ag
N.B-If x moles of copper is produce then the moles of silver that will be produced will be 2x moles.

Boss what about the solution to your question...

buzyguy: Itz electrochemical wen zinc acts as the anode nd fe,cathode bcuz znc z grter dan iron in da e.c.e series.i bliev u already knw dat,nd electrolytc wen znd z cathode nd iron z anode...u knw wen u get to electrolytc cells,itz alwyz reversed to da combinatn in electrochmical cell.hop it makz sense?!

Boss you are confused...option A is electrolytic and you saying the reaction is electrochemical....Option B is one of the uses of electrolysis....remember not all answers in the past questions are correct...

Those with past questions shud bring in questions especially calculations as its most people's prob.

buzyguy: Which of the following can be adopted to prevent rustinga)eletrolytic,cathodic protectn by making zinc the cathode and iron the anode (b)electrolytic cathodic protection with the anode zinc and cathode iron (c)electrochemical,with the anode iron and cathode zinc (d)electrochemical,with the anode iron and cathode tin?

B is the answer as zinc have to lose electrons xo etas to be the anode as the positive electrode...The process is called galvanisation...

Nemidav: My brodas,who cn explain calculation based on faraday's law?dunno y ts giving me problems.

Trying solving with this formula
M = MmIT/zf

wie
M is mass
Mm is molar mass
I is current
T is time
z is the charge on the ion
f is the 96500

joseboy199: Ans is B
equilibrium constant Kc=products/reactants.
it is products over d reactants...the law bhind aw equilibrium constant Kc is law of active mass
the number of mole of each compounds is written inform of power.e.g 2NH3 wic z naw written as {NH3}*2,

Nice one...

joseboy199: nxt tym complete ur questn...u didnt gv us d electrochemical equivalent e.c.e...
steps 2 4low on aw 2 solve d que
formula 2 use z...M=ZIt,,whr
M=mass in gramms
Z=e.c.e
I=current in amperes
t=time
0.16=15*60(input d z here)*I
I=0.16/15*60*z
solve wen z gven by im

Not in all cases boss....calculations on electrolysis is in different dimensions....solve with jamb past questions and see the dimensions...different in physics and chemistry

joseboy199: continuation,,guy d equatn z nt balancd,hydrogen gas should av 3 mole..i.e 3H2,,,and is written as [H2]*3...and nitrogen is written as [N2] cuz d numba of mole z 1

The 3 had been input as the order of the reaction (i.e d power)....

Kunlexic: This is on electrolysis(Electrochemistry)
1.state the two laws of Michael Faraday on electrolysis
2.Calculate the current that will deposit 0.16g of copper in 15minutes from copper(III)tetraoxosulphate(VI) solution.

Always give options as we are preparing for jamb here
...will attempt the question anyway

Using M= MmIt/zf
wie M is mass
Mn is Molarmass
I is current
T is time
z charg of corper ion
F faraday
molar mass of CuSO4 is 159.5

M = MnIT/ZF

0.16 =159.5 * I * (15*60)/2 * 96500

0.16 = 143550I/193000

cross multiplyin...we have

0.16 * 193000 = 143550I


30880 = 143550I

I = 30880/143550

I = 0.215A

I = 0.2Ampere

N2 + 3H2 <===> 2NH3 Dh = -92kjmol^-1

The equilibrium constant for the reaction can be expressed as

A.Kc = 2[NH3]/3[H2] [N2]

B.Kc = [NH3]^2/[N2] [H2]^3

C. Kc = [N2] [H2}^3/{NH3}^2

D. Kc = 3[H2] [N2]/2[NH3]

[quote author=t.boy007]please teach us the calculations in energetics.....i mean all those heat of combustion,formation,e.t.c[/quote]Aiit boss buh I dnt tch we are all learning here....

LET THE QUESTIONS FROM IT ROLE IN......

Let more questions come in......

mayorall: What volume of gas is involved at s.t.p if 2g of caco3 is added to a solution of HCl

a.224cm3
b.112cm3
c.240cm3
d.448cm3

CaCO3 + 2HCl <===> CaCl2 + CO2 + H20

using
moles = mass gven/molar mass

moles =2/caco3
moles =2/100 (100 is d molar mass of caco3)

moles = 0.02mol

using the volume of gas at s.t.p formula

moles = volume/22.4dm3

0.02 = volume/22.4dm3

volume = 0.02 * 22.4dm3

volume = 0.448dm3

converting the volume to cm3 we multiply by 1000

volume= 0.448 * 1000
volume = 448cm3........D

Nemidav: Pls teach us d formular method too.

Aiit master......

Nemidav: equation:H2SO4 + CuO-> CuSO4 + H20
MASS NUMB OF H2SO4=98g
MASS NUMB OF CuO=79.5g
if 98g of H2SO4 will react with 79.5g of CuO
then 4.9g of H2SO4 will react with xg of CuO
THEN X=79.5*4.9/98
x=465.5/98=3.95
3.95 approx 4.
Ans=A

The answers are correct but its not mass number its molar mass H2SO4 and CuO are compound....

Please do you understand how he arrived at the answers...if No...we can use a formular method.

If a solutn contains 4.9g of H2SO4, calculate d amount of cuo that will react with it

a.4.0g
b.8.0g
c.0.81g
d.40g

What volume of gas is involved at s.t.p if 2g of caco3 is added to a solution of HCl

a.224cm3
b.112cm3
c.240cm3
d.448cm3

joseboy199: B,final answer

Yes boss....

Obinnau: 1: the pericardia is a very flat muscle which envelops the heart.
:2:don't know about 2
3:its d pancreas
4: reptiles and amphibians have a 3-chambered heart, mammals have 4 while fish have only 1 so the ansa is B.

Nice one boss....

Please bring in calculations......

mayorall: The organ situated in d pericardia cavity of a mammal is d
a.Heart
b.liver
c.stomach
d.spleen

2.The 4matn of water in tissue respiratn results from d
a.breakdown of water molecules
b.reductn of oxygen by hydrogen
c.reduction of co2
d.combination of water molecules

3.which of the followin produces hormones and enzymes
a.ileum
b.pancreas
c.gall bladder
d.kidney

4.which of the folowin vertebrates has most simple structured heart
a.Reptile
b.Fish
c.Mammal
d.amphibian

Answers.......

Obinnau: ok in my next ansa. Am I right though?

Not 100%...answer 3 is wrong........