216 - Chemistry Questions Answers

the correct increasing order of lattice energy of the above compounds is - AlF3 , Al2O3 and AlN

Asked By: SWATI KAPOOR
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Joshi sir comment

AlF3              5924 kJ/mol

Al2O3           15916 kJ/mol  

AlN               9506.8 kJ/mol

24.5g KClO3 heated to give O2, which is allowed to react completely with H2 to form H2O. This H2 comes from Zn and H2SO4 reaction. The amount of Zn required for the purpose is

Asked By: SWATI KAPOOR
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Joshi sir comment

2KClO3 ----------------------> 2KCl + 3O2

3O2 + 6H2 --------------------> 6H2O

6Zn + 6H2SO4 -------------------> 6ZnSO4 + 6H2

so 2 mole  KClO3  -----------------------------  6 mole Zn

now solve

Integral enthalpy of soln of KCl , when 1 mole of it is dissolved in 20 mole water is +15.90kJ . When 1 mole of it is dissolved in 200mole water  dH =15.58kJ. Calculate enthalpy of hydratn or dilutn ??

 

ans is 2.68kJ

Asked By: SARIKA
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Joshi sir comment

Integral enthalpy 

please check this word if wrong submit the correct question again

can anyone explain to me how to write the structures of some organic compounds like but-2-ol?

Asked By: ANURAG
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Joshi sir comment

name is not correct

IUPAC name has four part

Extra Group................Main Chain............Bond Name..............Main Group

so name may be

*****..........................but........................an...................................2ol

****** means no extra group is present 

Main group is alcohol and its name is ol, 2 for second place in chain

"but" for 4 carbon and "an" for all single bond

so structure will be     CH3CH(OH)CH2CH3

If the potential energy of hydrogen electron is -3.02eV in which of the following energy levels is electron present =

1st , 2nd , 3rd  or  4th 

Asked By:
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Joshi sir comment

Energy = -13.6/n2 ,  Potential Energy = -27.2/n2

for n = 3 we get -3.02  

in this answer infinite is zero potential energy level

A 0.5 g sample of sodium nitrate on heating gives 44.8ml of O2 at STP. % purity of the sample is.............

my answer is 64% but the correct answer is 68%. HOW???

Asked By: SWATI KAPOOR
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Joshi sir comment

NaNO3  −−−−>    NaNO2 + 1/2 O2

molar mass of sodium nitrate = 85

so 85 gm will give 11200 ml O2

so x gm will give 11200*x/85 = 2240x/17

on comparing with 44.8

we get 2240x/17 = 44.8

so x = 44.8*17/2240 = 17/50 = 34/100 = 0.34 gm

means 0.34 gm sodium nitrate is pure in 0.5 gm. sample so % purity = 0.34*100/0.50 = 68%

There is two atoms of 'P' in one molecule of a compound. If the compound contains 27.93% of phosphorus, the compound will be......

(atomic mass of P = 31)

 

Asked By: SWATI KAPOOR
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Joshi sir comment

question is not complete, you should give the information about other elements present.

 

 

the inverse of ratio of number of revolutions of electron per second in third and fourth of H-atom in terms of velocity (v) and radius (r) is

Asked By: SWATI KAPOOR
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Joshi sir comment

T α r/v    α is symbol for proportional

so f α v/r

v α 1/n

r α n2

now solve

Equivalent weight of A2O in the given reaction is A2O = AO             (molar mass of A2O = M)

Asked By: SWATI KAPOOR
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Joshi sir comment

O.N. change = 1-2 = -1

2 A are present so net change = 2

so e.w. = M/2

show that (du/dv)s=T-sdp

 

Asked By: KARTHIKCHEMIST
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Joshi sir comment

question is incorrect 

because (du/dv)s represents pressure and T is temperature

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