Chemistry: Post your doubts here!

[The Sarcastic Retard]

Oh yes sorry! it is C/.... how??

Volume: 1cm^3 of ice.
1cm^3 (1g / 1cm^3) : mass = 1g
n of H2O: 1/18
PV = nRT
V = nRT/P
V = [1/18 * 8.31 * 596]/101000 = 2.72 dm^3 (the difference in answers is rounding between steps)

 

[The Sarcastic Retard]

View attachment 54536
Isn't AlCl3 dimeric covalent? but answer is B...??

I had same doubt:¬
http://www.chemguide.co.uk/inorganic/period3/chlorides.html
If you can't get enough : http://openstudy.com/updates/53959dede4b01c619df1a33c

 

[shazmina]

Can any1 please help me with this question ........

Guys this Qs pls ............

 

[nehaoscar]

I had same doubt:¬
http://www.chemguide.co.uk/inorganic/period3/chlorides.html
If you can't get enough : http://openstudy.com/updates/53959dede4b01c619df1a33c

The first link agrees that AlCl3 should be the answer?

 

[The Sarcastic Retard]

Guys this Qs pls ............

C ?

 

[The Sarcastic Retard]

The first link agrees that AlCl3 should be the answer?

It is IONIC with lot of covalent character..

 

[nehaoscar]

It is IONIC with lot of covalent character..

So AlCl3 is ionic with a LOT of covalent character
And MgCl2 is ionic with SOME covalent character as specified in the question?

 

[♣♠ Magnanimous ♣♠]

The first link agrees that AlCl3 should be the answer?

It is C
because

PV = nRT

n = mass/Mr

so, PV = mRT/Mr

Mr = mass * R * T /PV

By this equation we get Mr is directly proportional to TEMPERATURE and inversely proportional to PRESSURE.

Conclusion ---> High temp and low press

 

[The Sarcastic Retard]

So AlCl3 is ionic with a LOT of covalent character
And MgCl2 is ionic with SOME covalent character as specified in the question?

AlCl3 is ionic with a LOT of covalent character but as it vaporises, its structure changes to covalent from ionic.

 

[nehaoscar]

Why??

 

[nehaoscar]

Why is 3 wrong?

 

[nehaoscar]

AlCl3 is ionic with a LOT of covalent character but as it vaporises, its structure changes to covalent from ionic.

Ok but then the question only asks about AlCl3 right (which thus is ionic with covalent character)
The link doesn't say that MgCl2 is ionic with covalent character
So then why is the answer MgCl2 that has an ionic structure with covalent character?
Why not AlCl3?
I'm sooo confused on this one xD

 

[The Sarcastic Retard]

Ok but then the question only asks about AlCl3 right (which thus is ionic with covalent character)
The link doesn't say that MgCl2 is ionic with covalent character
So then why is the answer MgCl2 that has an ionic structure with covalent character?
Why not AlCl3?
I'm sooo confused on this one xD

Metanoia

 

[fantastic girl]

View attachment 54538
Why is 3 wrong?

It's not a reaction undergone by hydroxyl grps

 

[qwertypoiu]

View attachment 54536
Isn't AlCl3 dimeric covalent? but answer is B...??

The question says: "Which chlorine compound has bonding that can be described as ionic with some covalent character?"
AlCl3 is actually a covalent compound, it's NOT ionic. Aluminium OXIDE, which reacts with both acids and bases, lis amphoteric.
NaCl when dissolved in water forms a solution with pH of 7. It forms Na+ ions and Cl- ions. It is completely ionic. AlCl3, being covalent (and not ionic), hydrolyses in water and forms Al(OH)3 and HCl. The resulting solution has a pH of 3.
MgCl2 can be described as ionic but forms a solution with pH of 6.5 when dissolved in water. The slight acidity is attributed to the slight covalent character.
So again, AlCl3 cannot be described as ionic, rather it is a covalent compound. So the right answer is MgCl2.

The reason for covalency in AlCl3 is the high charge density of Aluminum ion, and large electron cloud of chlorine atom. Aluminum fluoride, for example, is ionic, since fluorine electron clouds are not large enough to be polarised by aluminum ion.

 

[qwertypoiu]

Guys this Qs pls ............

The equation applies for ideal gases. Ideal gases do not have intermolecular forces.
High temperature and low pressure encourage low intermolecular forces.

 

[hassannouman]

View attachment 54538
Why is 3 wrong?

because PCl5 or SOCl2 is used in step Y and white fumes of HCl gas are produced, Sodium ion in NaCl can not protonate OH group

 

[shazmina]

Help please!!!!!!!!!
The conversion of graphite into diamond is an endothermic reaction (∆H = +3 kJ mol–1).

C(graphite) → C(diamond)

Which statements are correct?

1 The enthalpy change of atomisation of diamond is smaller than that of graphite.

2 The bond energy of the C–C bonds in graphite is greater than that in diamond.

3 The enthalpy change of combustion of diamond is greater than that of graphite.

Ans is A

 

[shazmina]

The equation applies for ideal gases. Ideal gases do not have intermolecular forces.
High temperature and low pressure encourage low intermolecular forces.

Thank you soooooooo much ... i actually didnt read the Qs properly ... anywys thank you so much

 

[shazmina]

It is C
because

PV = nRT

n = mass/Mr

so, PV = mRT/Mr

Mr = mass * R * T /PV

By this equation we get Mr is directly proportional to TEMPERATURE and inversely proportional to PRESSURE.

Conclusion ---> High temp and low press

Thanks alotttttttttt