calcium carbonate q (2 Viewers)

[alluring]

yes, BOS chem markers know

hahaha, i love you serge..
damn smart ass
thanks for your help, much appreciated

 

[kouklitsa]

The molar ratio was such that you had to halve the number of moles i.e. 0.5 x 0.0136 x 100.09 = 0.68g.

perfect thats exactly what i got!

 

[lala2]

I didn't know what to do with the excess HCl, so I simply pretended that that part of the question wasn't there, and calculated it to be like 0.8g. Oh well, they have to give me marks for knowing the correct setup (as though the excess HCl part of the question wasn't there).....right???!!!

 

[treelovinhippie]

oh truck!

CaCO3 + 2HCl -> H2O + CO2 + CaCl2

Damnit... I did that but couldn't balance it (I must've forgotten the Cl2 part)... so then I changed it to something else.

damn

 

[Captain Karl]

oh truck!

CaCO3 + 2HCl -> H2O + CO2 + CaCl2

Damnit... I did that but couldn't balance it (I must've forgotten the Cl2 part)... so then I changed it to something else.

damn

Isnt the equation

CaCO3 + 2HCl -> CaCl2 + H2CO3?

 

[treelovinhippie]

Isnt the equation

CaCO3 + 2HCl -> CaCl2 + H2CO3?

hmm, hoepfully, that's the second equation I put I think

 

[alia]

im not too sure about that because When CaCo3 reacts with acid, H2 gas evolves.

But they might accept it cos it's balanced and H20 + CO2 --> H2CO3

 

[Captain Karl]

I'm not sure which one's right but i think that i might've gotten it wrong. Thank god the molar ratios ended up the same so i could at least get part of the question right

 

[kouklitsa]

acid + carbonate ---> salt + water + carbon dioxide... year 8 chemistry

but did they actually ask for the equation? i cant remember.. if they didnt they cant take a mark away from you. and if you got your moles ratios right then there shouldnt be a problem

 

[alia]

yes they did ask for a balanced equation

 

[Captain Karl]

acid + carbonate ---> salt + water + carbon dioxide... year 8 chemistry

It all came flooding back to me after I left the exam. At most it'll be 1 mark that gets taken away but.

 

[kouklitsa]

It all came flooding back to me after I left the exam. At most it'll be 1 mark that gets taken away but.

now that im thinking about it im trying to remember whether i put in the subscripts.. coz apparently they were gonna start taking marks off for that too!! im pretttty sure i put it but cant remember now! argh

 

[Captain Karl]

By subscripts do you mean solid (s), gas (g) or aqueous (aq)? I think they do take marks off for that coz for the last two years my teacher would always tell people what state they're in. We used to get marks taken off for it in internal exams at least

 

[kouklitsa]

By subscripts do you mean solid (s), gas (g) or aqueous (aq)? I think they do take marks off for that coz for the last two years my teacher would always tell people what state they're in. We used to get marks taken off for it in internal exams at least

yep... thats what i meant, and our teacherwould do that in internal exams.. but up until last year when she was marking hsc they werent taking marks off.. she said they might this year though. and they dont give half marks so that'd be bad if i didnt put them :|

 

[Captain Karl]

Usually it shouldnt matter unless its a question regarding states of matter (like the ammonia question, but we were already given that equation so it didnt matter in that question). If it was about observing the CO2 bubbles or something we'd need it. I'm not sure how lenient they'll be in that sense so even if you didnt put states in it might not matter