Chemistry Predictions/Thoughts (2 Viewers)

[coolcat6778]

what did you guys get for when the inert gas was added to the system of constant volume? was it meant to be eqm doesnt shift because volume is constant so increased pressure doesnt change the concentration of reactants or products? i think i did it wrong

this was the only question i could do

 

[nowomansland]

what did you guys get for when the inert gas was added to the system of constant volume? was it meant to be eqm doesnt shift because volume is constant so increased pressure doesnt change the concentration of reactants or products? i think i did it wrong

why was rhat 4 marks bro

 

[nowomansland]

this was the only question i could do

what did u say

 

[YulianaTheAmogusArtist]

this was the only question i could do

how did you do it?

 

[coolcat6778]

what did u say

"The addition of argon gas increases the pressure... bla bla bla"

By transforming the equation into 2NO2(g) <-> N2O4(g) + Heat , it becomes clear what happens

 

[dubbatee]

Wait so it’s one?? I said it will preferentially ppt with OH- first so I did Ksp calculation and check the remaining OH- available for Co32- and if ppt can occur with that

I think for that question we can make a pretty accurate assumption that Mg2+ and OH- react to completion. The reason we deal with Mg(OH)2 first is because the molar solubility of Mg(OH)2 is less than that of MgCO3, ie it will precipitate out the Mg2+ ions first. In the Mg / OH reaction, Mg2+ is the excess reagent and after the reaction we have 0.001M (or very very close) of Mg2+. If we find the QSP of the dissolution of MgCO3, we see that Qsp = 0.001 * 0.002 = 2x10^(-6) < Ksp - 6.82 x 10^(-6), so no precipitate forms. Would check using molar solubility for both tho

 

[nowomansland]

"The addition of argon gas increases the pressure... bla bla bla"

By transforming the equation into 2NO2(g) <-> N2O4(g) + Heat , it becomes clear what happens

so temp increases right

 

[YulianaTheAmogusArtist]

I did the calculation and there is enough excess Mg2+ to precipitate with both the carbonate and hydroxide ions. I said 2.

i think its like the number of mols of mg2+ excess is lower than the molar solubility of mgco3, so there isn't enough mg2+ to ppt it will still be solubl

 

[coolcat6778]

so temp increases right

yup

 

[lazystudentzzz]

"The addition of argon gas increases the pressure... bla bla bla"

By transforming the equation into 2NO2(g) <-> N2O4(g) + Heat , it becomes clear what happens

how would adding inert gas impact the temp tho? i thought it would only slow down the reaction from whati wastaught

 

[nowomansland]

i think its like the number of mols of mg2+ excess is lower than the molar solubility of mgco3, so there isn't enough mg2+ to ppt it will still be solubl

oh shit i didn’t calc molar solubility for the second one can i get 2 marks atleast ugh

 

[nowomansland]

how would adding inert gas impact the temp tho? i thought it would only slow down the reaction from whati wastaught

i didn’t understand it either so i just yapped and said it will increase pressure so system will shift right and in doing that the temp will increase bc it’s an exothermic reaction

 

[coolcat6778]

No temperature change

 

[ritzcrackers]

has anyone found answers for the 2025 chem HSC?

 

[lazystudentzzz]

View attachment 50270
No temperature change

yeah im pretty sure this is what i said thanks!!

 

[YulianaTheAmogusArtist]

yup

but I think its like the addition of inert gas doesnt shift eqm at all, because volume is constant, someone showed me in some theory after, seems legit. I think temp decreases actually because youre adding more gas which is gonna absorb some of the heat and lower overall temp. but the addition of inert gas in constant volume doesnt shift eqm. im stupid

 

[nowomansland]

View attachment 50270
No temperature change

great -4 marks

 

[dubbatee]

i didn’t understand it either so i just yapped and said it will increase pressure so system will shift right and in doing that the temp will increase bc it’s an exothermic reaction

I think the question is bit misleading for 4 marks. I think the markers want you to talk about how the addition of the inert gas, argon, does not affect the partial pressures of each individual gas since the volume is fixed in this container. Furthermore, there will be no actual disturbance received by the system and thus the equilibrium position does not change. Hence, the system will not shift in any direction, and thus the temperature will not change

 

[YulianaTheAmogusArtist]

can someone explain why 19 is c?

 

[coolcat6778]

great -4 marks

the least they will give is 1