How much ammonia is needed to form 1.0 kg of nitrogen? I would assume you'd just divide 1000g by 14.01 g?

Question

Is that how you do it?

Answer 1

I am a little confused by your question, do you mean how much ammonia do I need to decompose to give 1 kg of Nitrogen gas?

2NH3 <--------> 3H2 + N2

So 2 moles of NH3 is required to make 1 mole of nitrogen

Moles of N2 in 1kg

moles = mass / molecular weight

molecular weight N2 = 2 x 14.01 = 28.02 g/mol

moles N2 = 1000g / 28.02 g/mol

= 35.69 moles of N2 in 1kg

Therefore, since you need 2 moles NH3 to make 1 mole N2. Then starting moles of NH3 = (2 x 35.69)

= 71.38 moles

You need 71.38 moles of NH3 are required to produce 1 kg of N2

Mass NH3 in 71.38 moles

mass = moles x molecular weight

molecular weight NH3 = 14.01 + (3 x 1.008) = 17.034 g/mol

So mass NH3 needed = 71.38 x 17.034

= 1215 g

= 1.2 kg of NH3

Answer 2

No. You divide by 17.01 since ammonia has a molar mass of 14.01+3*1=17.01

so 58.79 moles of NH3