dextercioby said:
The second one is really easy,textbook i might say.
Cu+HNO_{3}\rightarrow \mbox{salt}+\mbox{oxyde}+\mbox{water}
Daniel.
Unfortunately the question is asking for ions not just the movement of substances. And also it is an ACID + METAL reaction and those reactions always give hydrogen + salt.
So you must consider whether the elements will lose electrons (as metals do) to become stable (a full outer shell of electrons) or whether they need to gain electrons (as non-metals do).
In the case of the former, the ions formed are of course +ve as the -ve charge of the atom (the electron) has been made smaller by its removal.
Conversly, for a non-metal the ve charge becomes bigger as more electrons (and therefore more -ve charge) is present.
It may be helpful, to write out the ionic equation and then figure out which ones don't change.
i.e.
Cu^+^2+2(H^+NO_{3}^-)\rightarrow\mbox{Cu^+^2 (NO_{3})_{2}^-}+H_{2}
sorry - but for some reason the LaTeX image won't form or i fit does it is not the image i requested! - hopefully somebody can tell me where i have gone wrong, as the image shows up when i preview the post!
The equation I was trying to show however is this
(Cu^+2) + 2({HNO_{3}^-) goes to (Cu^+^2) (NO_{3})_{2}^-}+ H_{2}
(A + or - with no number after it indicates a +1 or -1 charge respectively.
As you know all compounds must be neutral in their charge. Therefore there has to be 2 nitrates to every 1 copper as copper has a +2 charge and nitrate has a -1 charge. Please also note the Nitrate is treated as an element - this is because it is what is known as a free radical.
The two is added before the nitric acid on the LHS (left hand side of the equation) to balance the number of hydrogen and nitrate molecules on each side - as in every chemical reaction nothing is lost (conservation of mass).
N.B. The hydrogen forms H_2 as it is a diatomic gas (it needs to atoms to be a stable compound with a H-H covalent bond)
As regards the first question, I am not sure where to start, if you post the whole equation here it would be helpful, or you may now see how to balance the equation and represent the ions.
Finally, in the equation shown it is an ionic equation as it shows the movement of ions.
Regards,
Ben