Net Ionic Equations: Balancing & Gases/Liquids

[dnt]

Homework Statement

solid ammonium dichromate will produce (when heated) solid chromium (IV) oxide, nitrogen gas, and water vapor. Write the balance equation and net ionic equation.

Homework Equations

First i wrote:

(NH4)2Cr207 (s) --> CrO2 (s) + N2 (g) + H2O (g)

The Attempt at a Solution

first i just cannot balance this thing. I am usually very good at it but this one doesn't seem to work. do i have it written down correctly so far?

secondly, in net ionic equations, what do you do with gases (and liquids)? i know solids do not ionize so you do not change them. but in this case, are there ANY ions? how can i write a net ionic equation here?

also if the molecule is molecular (covalent) does it ionize at all or do you also just leave it? can it "dissolve" in solution (eg CO2)? i would assume you do not change it since it is made up of covalent bonds and not ionic ones. hence it written the same in the net ionic equations.

thanks for the help.

 

[t!m]

Don't worry - you can't balance the equation because there's a mistake in the problem. Ammonium dichromate, when heated, decomposes into chromium (III) oxide, nitrogen gas, and water vapor. The green color left behind is indicative of chromium (III) oxide. That should make things easier for you.

 

[dnt]

thanks.

does anyone know the other questions? what do you do with gases and liquids for net ionic equations? what about covalent molecules?

 

[Borek]

Just left them if necessary.

2H⁺ + Zn(s) -> H₂(g) + Zn²⁺

Borek