Ammonia reacts with oxygen according to the equation 4nh3(g)+5o2(g)→4no(g)+6h2o(g),δhrxn=−906 kj calculate the heat (in kj) associated with the complete reaction of 155 g of nh3. express the heat in kilojoules to three significant figures.
155 g of NH3 = 9.10 moles
Heat released = 9.10 moles * [ -9 kJ/4 moles NH3 ] = -20.5 kJ
(278 g NH3) / (17.03056 g NH3/mol) x (-906 kJ / 4 mol NH3) = -3697 kJ
[or maybe omit the minus sign].
Its a HESS reaction.
