• Best of luck to the class of 2025 for their HSC exams. You got this!
    Let us know your thoughts on the HSC exams here

Chemistry Predictions/Thoughts (2 Viewers)

Trial&Error

Well-Known Member
Joined
Nov 18, 2024
Messages
333
Gender
Female
HSC
2025
What was ka of acid in the titration curve question? And why did ph of naoh 0.1 mol/l never reach 13
For a weak acid u look at the 1/2 equivalence point where pH=pKa, then solve for Ka
Because for 13pH to happen the conc of OH- has to be 0.1mol/L which can’t occur since some of the OH- is neutralised by the H+ from the weak acid.
 

Trial&Error

Well-Known Member
Joined
Nov 18, 2024
Messages
333
Gender
Female
HSC
2025
Question. For the titration question I got 86.7% which didn’t align with anything, and I double checked and there was no rounding errors either. so I put X and said after accounting for rounding and titration inaccuracies, it’s closest to 85.5%. Is that okay do you guys think?
 

Starship22

Member
Joined
Apr 4, 2023
Messages
31
Gender
Male
HSC
2025
for the Ka x Kb question, I accidentally did N2H4 + H2O —> OH- + N2H5+ so I got POH as like 4.46. How many marks would I lose for this
 

anonymoushehe

Active Member
Joined
Apr 15, 2022
Messages
299
Location
Newcastle, NSW
Gender
Male
HSC
2025
Question. For the titration question I got 86.7% which didn’t align with anything, and I double checked and there was no rounding errors either. so I put X and said after accounting for rounding and titration inaccuracies, it’s closest to 85.5%. Is that okay do you guys think?
bro I think me too my percentage was slightly above but I didn’t round in my calculations until end
 

nowomansland

Active Member
Joined
Jun 11, 2024
Messages
162
Gender
Female
HSC
2025
Question. For the titration question I got 86.7% which didn’t align with anything, and I double checked and there was no rounding errors either. so I put X and said after accounting for rounding and titration inaccuracies, it’s closest to 85.5%. Is that okay do you guys think?
yeah thats fine i also got 85.7% but i don’t think we had to justify it i just said it was closest to brand X
 

Users Who Are Viewing This Thread (Users: 0, Guests: 2)

Top