Chemistry: Post your doubts here!

[Namehere]

Oh boy. That's a toughie.

Group II metal nitrate upon heating will produce a metaloxide and NO2 in 1:1

X(NO3)2 -> XO + NO2

Umm. I'd probably tackle it by finding the mols of the metal nitrate and metal oxide in terms of x.

5/(x+(2(14+16*3)=5-3.29/(x+16)
5/x+124 = 1.71/x+16
5x+80 = 1.71x + 212.04
3.29x = 132.04
x = 40.1
so, Calcium.

The equation for the Group II nitrate thermal decomposotion is as follows: 2X(NO3)2 ----> 2XO + 4NO2 + O2
5.00g 1.71g (all 3.29g)

You could do it using a bit of algebra or through trial and error. So:
if X = Mg, number of moles of Mg(NO3)2 = 5/148.3 = 0.0337 mol.
Therefore mass os MgO produced = 0.0337 x 40.3 = 1.36g, so can´t be Mg.

if X=Ca, number of moles of Ca(NO3)2 = 5/164.1 = 0.0305 mol.
Therefore mass of CaO produced = 0.0305 x 56.1 = 1.71g

Best way will be fastest way! ^^

 

[Namehere]

Btw any idea what is the colour of ( [Ag(NH3)2]+2 Cl-1 ) ?

the reaction of AgCl + NH3

Well AgCl is a white precipitate. If you add NH3 it usually dissolves.

Do correct me though.

 

[Haya Ahmed]

Well AgCl is a white precipitate. If you add NH3 it usually dissolves.

Do correct me though.

Yeah right .. I totally forgot about the solubility thingy

 

[AbbbbY]

The equation for the Group II nitrate thermal decomposotion is as follows: 2X(NO3)2 ----> 2XO + 4NO2 + O2
5.00g 1.71g (all 3.29g)

You could do it using a bit of algebra or through trial and error. So:
if X = Mg, number of moles of Mg(NO3)2 = 5/148.3 = 0.0337 mol.
Therefore mass os MgO produced = 0.0337 x 40.3 = 1.36g, so can´t be Mg.

if X=Ca, number of moles of Ca(NO3)2 = 5/164.1 = 0.0305 mol.
Therefore mass of CaO produced = 0.0305 x 56.1 = 1.71g

Best way will be fastest way! ^^

My equation is intentionally unbalanced. All I wanted to show was the X(NO3)2 -> XO in a 1:1

And yes. Trial and error + quick calculator work will be quick too.

 

[itallion stallion]

Help needed!
How to draw structure of XeF4( it has 4 bonding pairs and lone pair also)?bond angle also plz?

 

[♣♠ Magnanimous ♣♠]

Help needed!
How to draw structure of XeF4( it has 4 bonding pairs and lone pair also)?bond angle also plz?

 

[kitkat <3 :P]

which alkane withthe least number of carbons can have a chiral centre????

 

[Haya Ahmed]

Any Idea how to solve this ... can someone help me please ?

 

[Haya Ahmed]

anyone explain please ?

 

[itallion stallion]

anyone explain please ?

In phenyl ethanoic acid u see that there is an addition of carbon,which always means that there must be an addition of CN group which replaced another group,Cl in this case.the addition of carbon is in the form of -CooH which means that CN group was hydrolysed.Rest u just need to learn the reagent and condition.

 

[Haya Ahmed]

In phenyl ethanoic acid u see that there is an addition of carbon,which always means that there must be an addition of CN group which replaced another group,Cl in this case.the addition of carbon is in the form of -CooH which means that CN group was hydrolysed.Rest u just need to learn the reagent and condition.

Thanks can U help me in this also ?

 

[itallion stallion]

Plz help me with these questions
Octobernovember 2009 paper42 q5 part A.
Octobernovember 2009 paper41 q3 bi and bii
October November 2008 paper4 q2 part b.
THANKS!!

 

[Haya Ahmed]

Someone help me please how to do this ?

 

[itallion stallion]

Thanks can U help me in this also ?

Sorry I can't.all I can say is that for option a charge on the cation will only determine strength of metallic bonding and lattice energy.ratio of charge will only tell the formula.like Mg has charge +2 and cl-1 so compound formula will be mgcl2.Option c seems appropriate.never heard anything like sum of charges so no simply.

 

[Haya Ahmed]

CAN ANYONE HELP PLEASE !

 

[kitkat <3 :P]

5 I guess.2-dimethyropane

but if the will be 2 methyl 2 same groups will be 2 same groups wont they :/>??

 

[Haya Ahmed]

Oct 2010 - Q8 - Ca(S) --> Ca(g) is +177
then add ionisation energies 1 and 2 wich are 590 and 1150
then Ca+2(g) --> Ca+2(aq) is -1565
so 117+590+1150-1565 = 352

Q25- a is cracking wich needs 500 degree. b needs reflux in ethanol so high temp needed. c also needs heating. only d doesnt need to be heated.

can you explain Question 8 Oct 2010 please more briefly because I didn't get it

 

[itallion stallion]

but if the will be 2 methyl 2 same groups will be 2 same groups wont they :/>??

Really sorry!u are right it will not be chiral then.2-ethyl pentane.7 carbons required.no of carbons can't be lesser than this.

 

[kitkat <3 :P]

Really sorry!u are right it will not be chiral then.2-ethyl pentane.7 carbons required.no of carbons can't be lesser than this.

thanks ^_^

 

[NinjaInPyjamas]

CAN ANYONE HELP PLEASE !

I got this cleared

https://www.xtremepapers.com/commun...st-your-doubts-here.9859/page-385#post-749053

credit to AbbbbY