Please help! I have tried this backward, forward, upside down, inside out, etc.
ID: 850516 • Letter: P
Question
Please help! I have tried this backward, forward, upside down, inside out, etc. and can't seem to come up with the correct answer. Please give an explanation so I can understand what I am doing incorrect.
Ammonia (NH3) decomposes to hydrogen and nitrogen and 22.0 kcal/mol of energy is absorbed.
2 NH3(g) ----> 3 H2(g) + N2(g) ?H= +22.0 kcal/mol
How much energy is absorbed when 1.59g of NH3 reacts?
___________kcal of energy absorbed.
Report your answer to appropriate number of significant figures.
Explanation / Answer
Molecular weight of NH3 = 17
=> no. of moles of NH3 = 1.59/17 = 0.0935 moles
Decomposition of 2 moles of NH3 abrsorbs 22kcal,
So energy absorbed when 1.59g NH3(=0.0935mol) decomposes = 0.0935 * 22 / 2 = 1.03 kcal