Chem revision question (1 Viewer)

spammy679

MLIA
Joined
Aug 23, 2007
Messages
193
Location
your room
Gender
Male
HSC
2010
ok the whole question is:

"0.30 moles of magnesium oxide is completely dissolved in nitric acid (HNO3) to form a solution of magnesium nitrate. Calculate the number of moles and masses of: a) nitric acid required and b) magnesium nitrate formed"

the thing i cant get around is what else is produced besides Mg(NO3)2. Is is H2O or OH? or anything else? if not, where does the hydrogen go?

thanks :D

P.S. yearlies are so demanding:sleep:
 

zaa

New Member
Joined
Aug 3, 2008
Messages
14
Gender
Female
HSC
2010
I'm pretty sure magnesium oxide is a base, so this is a neutralisation reaction (acid + base - -> salt + water)
So the other product should be water :)
Hope this helps
 

randomnessss

Member
Joined
Oct 11, 2008
Messages
91
Gender
Male
HSC
2010
Uni Grad
2015
MgO (s) + 2HNO3 (aq) ----> Mg(NO3)2 (aq) + H2O (l)

This is a neutralisation reaction, and hence, acid + base ----> salt + water, where MgO is a base (metallic oxides are generally bases) and HNO3 is an acid.
In regards to your question, the hydrogen is covalently bonded to oxygen to form water.

Theoretical mole ratio - n(Mg):n(HNO3):Mg(NO3)2:H2O = 1 : 2 : 1 : 1
Therefore 0.3 moles of Mg react with 0.6 moles of HNO3 form 0.3 moles MgO and 0.3 moles of water.

Mass of HNO3 = nM
= 0.6 x (1.008+14.01+3(16))
= 37.8108 g


Mass of MgO = nM
= 0.3 x (24.31+16)
= 12.093 g
 
Last edited:

spammy679

MLIA
Joined
Aug 23, 2007
Messages
193
Location
your room
Gender
Male
HSC
2010
cool
thanks a lot :p

good luck in exams, or if you already had them, hope you all did well
 

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

Top