16) 3.25 kcal is the same amount of energy as A) 3.25 J. B) 0.777 J. C) 777 J. D) 13600 J. E) 13.6 J.

option D 13600 J

Explanation:

This is actually a simple convertion problem. the energy expressed as heat in calories, has a convertion in Joules.

In the case of cal to Joules is the following:

1 cal > 4.184 J

So, let's convert first the kcal to cal:

3.25 kcal * 1000 cal/kcal = 3250 cal

Now, using the conversion factor of above we have:

J = 3250 cal * 4.184 J/cal

J = 13,598 J or rounded to 13,600 J option D

n2(g) + 3h2-> 2nh3(g)   this is the balanced equation

note the mole ratio between n2, h2 and nh3.   it is 1 : 3 : 2   this will be important.

moles n2 present = 28.0 g n2 x 1 mole n2/28 g = 1 mole n2 present

moles h2 present = 25.0 g h2 x 1 mole h2/2 g = 12.5 moles h2 present

based on mole ratio, n2 is limiting in this situation because there is more than enough h2 but not enough n2.

moles nh3 that can be produced = 1 mole n2 x 2 moles nh3/mole n2 = 2 moles nh3 can be produced

grams of nh3 that can be produced = 2 moles nh3 x 17 g/mole = 34 grams of nh3 can be produced

note:   the key to this problem is recognizing that n2 is limiting, and therefore limits how much nh3 can be produced.