The Student Room Group

Chemistry C2 - Help Please

Hey, our teacher sets us these sheets to see whether or not we understand them. Don't get confused they are not homework sheets we don't return them to her its for out own benefit. Can anyone help me with the following question. I don't expect an answer just something to get me started on it because i wasn't in the lesson we were taught this.

d i) Balance the equation:
Mg + 4HNO3 --> Mg(NO3)2 + 2 H2O + 2NO2
The red is what i filled in, is it correct?

d ii)The toxic gas was nitrogen dioxide NO2. Calculate the mass of nitrogen dioxide produced when 96g of magnesium reacts completely with nitric acid. (Relative atomic masses: N=14, O=16, Mg=24)

.......

Any help will be really appreciated. I really need to learn this topic.:smile::smile:
(edited 9 years ago)
Original post by Aty100
Hey, our teacher sets us these sheets to see whether or not we understand them. Don't get confused they are not homework sheets we don't return them to her its for out own benefit. Can anyone help me with the following question. I don't expect an answer just something to get me started on it because i wasn't in the lesson we were taught this.

d i) Balance the equation:
Mg + 4HNO3 --> Mg(NO3)2 + 2 H2O + 2HO2
The red is what i filled in, is it correct?

d ii)The toxic gas was nitrogen dioxide NO2. Calculate the mass of nitrogen dioxide produced when 96g of magnesium reacts completely with nitric acid. (Relative atomic masses: N=14, O=16, Mg=24)

.......

Any help will be really appreciated. I really need to learn this topic.:smile::smile:


If by 2HO2 you actually mean 2NO2, then yes, that's correct.
The equation you need to use is: number of moles = mass / relative molecular mass. Work out the number of moles of Mg, use the equation in part d) to work out how many moles of NO2 it would produce, then use the equation to work out the mass of NO2.

Posted from TSR Mobile
Reply 2
Original post by whatacrydonnie
If by 2HO2 you actually mean 2NO2, then yes, that's correct.
The equation you need to use is: number of moles = mass / relative molecular mass. Work out the number of moles of Mg, use the equation in part d) to work out how many moles of NO2 it would produce, then use the equation to work out the mass of NO2.

Posted from TSR Mobile


oh yh sorry 2NO2 not 2HO2, typo sorry
And Thanks :smile:
Reply 3
Original post by whatacrydonnie
If by 2HO2 you actually mean 2NO2, then yes, that's correct.
The equation you need to use is: number of moles = mass / relative molecular mass. Work out the number of moles of Mg, use the equation in part d) to work out how many moles of NO2 it would produce, then use the equation to work out the mass of NO2.

Posted from TSR Mobile


Thanks for the help but i've been trying for about half an hour and keep getting different answers and am a little confused. I was able to do the rest of the questions though. If you don't mind can you show me how to complete this. Don't worry ill write it in green which shows i didn't do it myself and hopefully i can learn from this because i'm the only one in my class who was absent and we wont be going over this again because i do triple science and we have to move on C3 after we do the ISA.
Reply 4
Original post by whatacrydonnie
If by 2HO2 you actually mean 2NO2, then yes, that's correct.
The equation you need to use is: number of moles = mass / relative molecular mass. Work out the number of moles of Mg, use the equation in part d) to work out how many moles of NO2 it would produce, then use the equation to work out the mass of NO2.

Posted from TSR Mobile



Oh Never mind i think ive finally figure out what to do:
Mg = 24
NO2 = 46


96/24 = 4 Mol
4 x 2 = 8
8 x 46 = 368g
Answer ---> 368

Is that correct ?
Yup, that's what I got anyway :smile:

Quick Reply

Latest