1)The synthesis of ammonia is an exothermic process: N2+3H2(arrow) triangle h=-91.8kJ The enthalpy of the decomposition of ammonia would be:

a)-183.6 kJ b)-91.8 kJ c)+183.6 kJ d) +91.8 kJ

2)Calculate the energy released when 24.8 g Na2O reacts in the following reaction. Na2O(s)+2HI(g)(arrow)2NaI(s)+H2O(I) (Na=12.0 amu; O=16.0amu) triangleh= -12.00kcal

a)48.0 kcal b)0.207 kcal c)3.00*10to the second power kcal D) 2.42 kcal

3)what would likely happen if you were to touch the flask in which an endothermic reaction were occuring?

a)the flask would probably feel warmer than before the reaction started

b)the flask would probably feel cooler than before the reaction started

c)the flask would feel the same as before the reaction started

d)none of the above

4)you are holding a flask containing concentrated hydrochloric acid(HCI). When you drop a few pieces of zinc metal in the flask, the mixture begins to fizz and the flask becomes warm. the reaction occuring in the flask is?

Relevance

1) N2 + 3H2 ===> 2NH3 DH = -91.8 kJ

So 2NH3 ===> N2 + 3H2 DH = +91.8 kJ

2) Atomic weights: Na=23 O=16 Na2O=62

24.8gNa2O x 1molNa2O/62gNa2O x -12.00kcal/1molNa2O = -4.8 kcal

3) b) Cooler

4) Zn(s) + 2HCl(aq) ===> ZnCl2(aq) + H2(g)