How is your preperation for Chem Unit 2 ???

[Shoggaine]

kya samjhaoon?

I already did

 

[étudiante]

I already did

 

[DANGERBP]

partly yes, but we need to see the difference in electronegativity as well, but yes dat is also needed

ugh but how is tht differs ?? each thing would make n exact opposite thing woud it ?? =$

 

[étudiante]

ugh but how is tht differs ?? each thing would make n exact opposite thing woud it ?? =$

umm.... different elements have different electronegativity values so the greater the difference in values, the more ionic the bond. You can remeber dat stuff lyk halogen atoms and oxygen are more electronegative

 

[DANGERBP]

The size of the lattice enthalpy is governed by several factors, one of which is the distance between the centres of the positive and negative ions in the lattice. Forces of attraction are greatest if the distances between the ions are small. If the attractions are large, then a lot of energy will have to be used to separate the ions - the lattice enthalpy will be large.

The lattice enthalpies of both carbonates and oxides fall as you go down the Group because the positive ions are getting bigger. The inter-ionic distances are increasing and so the attractions become weaker.

but if lattice energy fall down the group ! why does thermal stability increase ??? =$

 

[DANGERBP]

when conc. H2So4 + NaBr > Br2 is formed
when its added to Nacl > no cl2 is formed whatss this exactly ?? why ??

 

[xIshtar]

but if lattice energy fall down the group ! why does thermal stability increase ??? =$

The thermal stability increases as down the group, the size of the cation increases. This means that the polarizing power is reduced, and thus the anion is more stable.
Also, the energy released as the 2+ and 2- charges get closer together is smaller.

 

[DANGERBP]

The thermal stability increases as down the group, the size of the cation increases. This means that the polarizing power is reduced, and thus the anion is more stable.
Also, the energy released as the 2+ and 2- charges get closer together is smaller.

thank u !

 

[DANGERBP]

guyz sn2 rxns help me in tht plz !

 

[xIshtar]

guyz sn2 rxns help me in tht plz !

What reactions?

 

[DANGERBP]

What reactions?

theres SN1 types n SN2 right ?
i no Sn1 which is by 1 step where a neucleophile attacks the carbo cat ion ! n the halogen is released by a heterolytic
but wat about Sn2 ?

 

[z3r0thunder]

For Carbonates in Group 2:
Size of Cation Increases
There are more electron shells
More distance from Nucleus of the outer electron
Therefore, the Cation is less Polarizing the Anion
Less distortion of the Anion's electron cloud.
More Thermally Stable.

 

[z3r0thunder]

when conc. H2So4 + NaBr > Br2 is formed
when its added to Nacl > no cl2 is formed whatss this exactly ?? why ??

Because both reactants have same Cation (Na)
Even if there was a reaction the products would stay the same.

 

[xIshtar]

when conc. H2So4 + NaBr > Br2 is formed
when its added to Nacl > no cl2 is formed whatss this exactly ?? why ??

Actually, it is because HCl is a weaker reducing agent, and thus this means that a redox reaction does not take place, and Cl2 is not formed.

 

[DANGERBP]

SN@ rxns ?? anyone ?? =S
nd guyz check this > 1 idodo butane or 1 chlorobutane has a higher boiling temperature ??
i thought it the chloro one but its the idobutane ? can someone explane why plzzz !
plus HF or H2O ? which one has a higher bp too ??
do we look for electronegativity in both or wat!!!
help ! asap !! thx

 

[DANGERBP]

Actually, it is because HCl is a weaker reducing agent, and thus this means that a redox reaction does not take place, and Cl2 is not formed.

oh seriously ? mmm Hcl is lower reducing agent because ??

 

[DANGERBP]

how to check for oxidation number for this rxn ! help plz z

K2CO3<aq> + Co2(g) + H2O<l> --- >> 2kHCO3 <aq>

 

[xIshtar]

oh seriously ? mmm Hcl is lower reducing agent because ??

HCl is not strong enough to reduce the H2SO4, and thus it means that chlorine is not produced.
On the other hand, as HBr is strong enough to reduce the H2SO4, Bromine is produced.

Water has a higher boiling point as it can form 2 hydrogen bonds.

 

[DANGERBP]

HCl is not strong enough to reduce the H2SO4, and thus it means that chlorine is not produced.
On the other hand, as HBr is strong enough to reduce the H2SO4, Bromine is produced.

Water has a higher boiling point as it can form 2 hydrogen bonds.

ugh m reall sorry botherin u allot !
but why is it not strong enough ? is it related to the electronegativity of it ? =$

yea its true for water , but the electronegativity of HF is higher ??

 

[xIshtar]

how to check for oxidation number for this rxn ! help plz z

K2CO3<aq> + Co2(g) + H2O<l> --- >> 2kHCO3 <aq>

Group one elements are always (+1)

Oxygen is generally (-2) And thus, Carbon in K2CO3 is (+4)

Carbon in CO2 is (+4) and Oxygen is (-2)

Hydrogen in H20 is (+1) and Oxygen is (-2)

In KHCO3, as K is (+1) and O is (-2), hydrogen is (+1) and thus carbon is again (+4)

I don't really get it