Charge on 1 g N3- ion

1. Apr 13, 2013

Alioth

1. The problem statement, all variables and given/known data
What is the charge in coulomb on 1 gram of N3- ions

2. The attempt at a solution
the atomic mass of nitrogen is 14 gram.
hence 14 g nitrogen will contain 6.022*10^23 ions.
therefore 1 g nitrogen will contain n=6.022*10^23/14 no. of ions.
one N3- ion has a charge of q=4.8*10^-19 C.
so n ions of N3- will carry a charge of n*q C= 2.065*10^4 C
But this answer is wrong. Where am I going wrong?
Does 14 g nitrogen contain Avogadro's no. of atoms?
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

2. Apr 13, 2013

Curious3141

The atomic mass of N is 14Da (it is NOT 14g!). But the molecular mass of N3- is 14*3 = 42Da.

Another mistake: the charge on one N3- ion is just e (a single electron charge).

Last edited: Apr 13, 2013
3. Apr 13, 2013

Staff: Mentor

Lousy typing gives lousy results. N3- and N3- are different things.

4. Apr 13, 2013

Curious3141

Very good point. He has to clarify if he meant nitride or azide (I assumed the latter).

5. May 7, 2017

Strawberry1711

Your solution is right but the question you ask for might be for 1 g-ion.
• 1 g-ion = (weight in grams of sum of atomic weight of atoms making the ion.)
• Here N^3- has 14 amu so 1g-ion 14 gm.
• So here we have to find for 14g that is 1mole of nitride ion.
1 ion of nitride has =1.6 ×10^-19 × 3 C
Therefore 6.022 × 10^23 ions has = 6.022 × 10^23 ×1.6 ×10^-19 × 3 C = 2.89 × 10^5 C.

Last edited: May 7, 2017
6. May 7, 2017

Staff: Mentor

Welcome to the PF @Strawberry1711 - just in case, please read the forum rules.

Stating that Coulomb equals Ampere definitely doesn't help. These are two different units.

7. May 7, 2017

Strawberry1711

Sorry
@Borek
It's 2.89 × 10^5 C.
And Thank you for telling me that I have corrected it.

Last edited: May 7, 2017