Chemistry: Post your doubts here!

[shinnyyy]

q2 is B
30%=mass of P2O5
? = mass of P2
cross multiply to get the answer

Omg someone replied so fast khud hi solve kr lia tha

 

[shinnyyy]

Q15 - see the ones which will decompose
B - MgCO3 -----> MgO + CO2 ---- u are getting one mole ov a gas which means its 24dm3
C- 2Mg(NO3)2 ------> 2MgO + 4NO2 + O2 ---- here its 5 moles of gas

Q20 -try out the structures....thats the only option
if u dont get it tell me

Q3-- its easy
write the equation first
C6H12 + 9O2 ------> 6CO2 + 6H2O
find the mass of CO2 nd H2O
6CO2 = 108
6H20 = 264
108/264 = .41

Tysm. .
ur boss is having some doubts in phy mcqs and p2 so I need some help in them

 

[Wkhan860]

Omg someone replied so fast khud hi solve kr lia tha

maine pehle dekha nhi tha
ek tu maine itni mushkil se data booklet dhondi...banda thank u hi bol deta hai -______-

 

[fantastic girl]

Tysm. .
ur boss is having some doubts in phy mcqs and p2 so I need some help in them

most welcome love :3
sure u can ask me.....i will explain if i know
i dont check these threads much so u can either post on my wall or ask in our crazy convo

 

[shinnyyy]

maine pehle dekha nhi tha
ek tu maine itni mushkil se data booklet dhondi...banda thank u hi bol deta hai -______-

Calm down man
I did say tysm lakin app nai solve kia so ty ty ty ty

 

[Wkhan860]

Calm down man
I did say tysm lakin app nai solve kia so ty ty ty ty

With the kind of dp u hav
Calming down isnt possible

 

[shinnyyy]

With the kind of dp u hav
Calming down isnt possible

Lolx it's kasba xD
Ahhhh then I have tonne of phy questions and I'll make you to solve them

 

[Wkhan860]

Lolx it's kasba xD
Ahhhh then I have tonne of phy questions and I'll make you to solve them

Hahahahha
Ok

 

[tahakay]

If they ask you to draw the Structure of the organic compound , you draw structural formula or Displayed formula ? This question came in june 2015 p22 and i drew structural , will i lose all of the marks of that question because of it ?

 

[_MoHD_E]

If they ask you to draw the Structure of the organic compound , you draw structural formula or Displayed formula ? This question came in june 2015 p22 and i drew structural , will i lose all of the marks of that question because of it ?

In p21 they asked us for skeletal formula . If they ask you to draw the structure of the compound and they didn't mention either displayed or skeletal then don't worry boss you are 100% correct . Structural formula is therefore what they want

 

[tahakay]

Thankyou ! Im sorry to ask you this , but how do you know this ? Did some teacher told you or something ?

 

[_MoHD_E]

Thankyou ! Im sorry to ask you this , but how do you know this ? Did some teacher told you or something ?

Hey boss check oct nov 2005 paper 2 question number 5 F) and check the marking scheme the question also asked to draw the structure of the compound and in marking scheme a structural formula is given so don't worry boss

 

[tahakay]

Bro thankyou :') !

 

[_MoHD_E]

Bro thankyou :') !

Don't mention it boss

 

[phanttasy]

The thermal decomposition of Group 2 decreases down the group is due to the cation increases in size, and small cation with higher charge tend to undergo thermal decomposition with large anion. What would happened if both cation and anion are small in size too?

 

[Metanoia]

The thermal decomposition of Group 2 decreases down the group is due to the cation increases in size, and small cation with higher charge tend to undergo thermal decomposition with large anion. What would happened if both cation and anion are small in size too?

The variables are size of cation and size of anion, during comparison, keep one variable to be the same.

same size cation, increasing size of anion --> decomposition temperature decreases

increasing size of cation, same size anion --> decomposition temperature decreases

 

[Knightmare11]

http://imgur.com/iyav9gY

Why is the answer C? Thanks!

 

[_MoHD_E]

http://imgur.com/iyav9gY

Why is the answer C? Thanks!

first option is wrong because ethanol is having a minus charge which means it has donated its H+ to sulphuric acid and sulphuric acid is accepting the H+ this cannot be because concentrated sulphuric acid is a far stronger acid than ethanol therefore sulphuric acid is the acid which is going to lose its H+ to ethanol. ethanol is going to behave slightly like a base in this reaction. the stronger acid in the reaction is the acid which is going to lose the H+.

 

[Abdel Moniem]

View attachment 55508
why is it D. can someone explain

PCl5(g)-->PCl3(g)+Cl2(g)
Enthalpy Change=Enthalpy change of bonds broken+ Enthalpy change of bonds formed
2 P-Cl bonds were broken and a Cl-Cl bond was formed

 

[Michelle Ngu]

on being heated the hydrogen iodide breaks down more quickly than hydrogen chloride.Which statement explains this faster rate?
1 HI bond is weaker than HCl bond
2 the reaction of breakdown of HI has a smaller activation energy than HCl
3 breakdown of HI is more exothermic than HCl
Why is 2 acceptable & why not 3 too?