Chem - independent paper 04 (2 Viewers)

[Premus]

Hey

can anyone pls tell me the answer to question 11? Im pretty sure its A, but is C also right?

Thanks

 

[jumb]

whats the question.

i did the paper but i dont have it infront of me

 

[Premus]

Nitrogen dioxide - brown gas - NO2 and
dinitrogen tetroxide - colourless gas- N2O4 are in equilibrium

2NO2(g) <-- --> N2O4(g)

If a Sealed tube of the gases is placed in an ice-water bath, the colour fades from brown to almost colourless. which conclusion is correct?

A) The forward reaction is exothermic
B) the reverse reaction is exothermic
C) the pressure has increased
D) the pressure has not changed

 

[Tommy_Lamp]

well think about it

if it is exothermic, the reaction will be as follows:
2NO2(g) <-- --> N2O4(g) + HEAT
so if it gets colder, then it will shift to the right, producing colourless N2O4, hence it is A

C is right but the the question is regarding temp

 

[mr EaZy]

how is pressure increased when the system is in isolation?
equilibrium only applies to closed systems.

 

[jumb]

Yeah hes right, the question has nothing to do with pressure.

 

[Paroissien]

This is the paper I did, and I have one question about it. Does anyone know why there where no longer response questions (worth like 7 or 8 marks)? Not that I'm complaining of course, because it made the paper a lot easier.