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2023 HSC chat (14 Viewers)

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user18181818

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i think it's correct
for the flame test between ba and ca don't you need to boil it or something because u can't do a flame test with them in ppt forms
 
Masaken

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SadCeliac said:
Shocker 😭 why does everyone think I'm gay
Self explanatory question but I'm still asking

View attachment 41115
Can anyone confirm if this elimination sequence is correct - HSC 2020 Chem paper
Click to expand...
cation looks correct but tbh you could've just said flame test without having the na2so4 bit since the three cations produce three distinct results (the colours of ba2+ and ca2+ and then you just say magnesium doesn't form a distinct colour). for anion, it's not AgOH that forms the precipitate - AgOH is formed but it's not stable so it decomposes into silver oxide (silver oxide is the brown precipitate you see) so you'd need to acknowledge that. Ag+ also forms a (white) precipitate with Cl- so you'd have to acknowledge that too but apart from that everything else looks fine
 
Masaken

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user18181818 said:
i think it's correct
for the flame test between ba and ca don't you need to boil it or something because u can't do a flame test with them in ppt forms
Click to expand...
they're all solutions though (specifies it's 0.1 mol/L at the start) so there's no ppt involved between ba2+ and ca2+
 
SadCeliac

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user18181818 said:
i think it's correct
for the flame test between ba and ca don't you need to boil it or something because u can't do a flame test with them in ppt forms
Click to expand...
Ok I'll keep that in mind - flame test the ions - got it

Masaken said:
cation looks correct but tbh you could've just said flame test without having the na2so4 bit since the three cations produce three distinct results (the colours of ba2+ and ca2+ and then you just say magnesium doesn't form a distinct colour). for anion, it's not AgOH that forms the precipitate - AgOH is formed but it's not stable so it decomposes into silver oxide (silver oxide is the brown precipitate you see) so you'd need to acknowledge that. Ag+ also forms a (white) precipitate with Cl- so you'd have to acknowledge that too but apart from that everything else looks fine
Click to expand...
Okay yeah I didn't know that, and I kinda ignored the AgCl ppt because it was the final thing anyways... Also I forgot the colour lol (white yeah?)

THANKS GUYS <3 🤩
Good to know I've memorised the colours of ppts basically fully correctly
 
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user18181818

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Masaken said:
they're all solutions though (specifies it's 0.1 mol/L at the start) so there's no ppt involved between ba2+ and ca2+
Click to expand...
yeah but then he's adding sulfate to it to make a ppt right? or you could take a new solution and do the flame test
 
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carrotsss said:
idk my english teacher seems like extremely confident ill b6 - she reckons im gonna get the second highest hsc mark in my yeargroup (we usually get 4-6 b6 for context) which is nice but idk if it’s like a false confidence
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How are you like almost SR in like every STEM subject there is and then are suddenly crazy at English as well?
 
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