HSC 2016 Chemistry Marathon (2 Viewers)

[BlueGas]

Re: HSC Chemistry Marathon 2016

5.00g table salt was dissolved in a 250L flask. He took a 10mL sample and diluted it to 1L for analysis. The absorbance was measured at 0.804.

From graph, 0.804 corresponds to 50ppm of sodium (50mg/L). Plz halp

What's the question?

 

[Zoinked]

Re: HSC Chemistry Marathon 2016

The question is

From graph, 0.804 corresponds to 50ppm of sodium (50mg/L). Plz halp

 

[mini8658]

Re: HSC Chemistry Marathon 2016

-ide - elements that react without oxygen
-ite - Elements that reacted with one less oxygen than they normally bond to
-ate - Elements that reacted with the number of oxygen molecules that they normally bond to
-per/ate-Elements that reacted with one additional oxygen molecule than they normally bond to

Help, I don't understand this. Isn't H2O called dihydrogen oxide so why does it have the ide ending? There's also CO and others...
And what do they mean by one less oxygen than they normally bond to? etc?

 

[someth1ng]

Re: HSC Chemistry Marathon 2016

-ide - elements that react without oxygen
-ite - Elements that reacted with one less oxygen than they normally bond to
-ate - Elements that reacted with the number of oxygen molecules that they normally bond to
-per/ate-Elements that reacted with one additional oxygen molecule than they normally bond to

Help, I don't understand this. Isn't H2O called dihydrogen oxide so why does it have the ide ending? There's also CO and others...
And what do they mean by one less oxygen than they normally bond to? etc?

-ide is usually an elemental ion (eg fluoride/F-, chloride/Cl-, azide/N3-).
-ide and -ate: when an element forms two different oxyanions (a polyatomic anion that contains oxygen), the one with less oxygen is -ite while the one with more oxygen is -ate (eg nitrite/NO2- vs nitrate/NO3-, sulfite/SO32- vs sulfate/SO42-)

 

[dan964]

Re: HSC Chemistry Marathon 2016

Closing thread. Please use the 2017 marathon.

Thanks