Paul's class investigated the effects of friction on the motion of a toy car. Using
ramps with different surfaces, students determined the amount of time, in seconds
(s), for the toy cars to reach the bottom of each ramp. All variables were controlled
except the tested variable (independent variable). Paul's group concluded that toy
cars on a sandpaper surface are fastest.
Which statement best evaluates the groups conclusion?
A. The results support the conclusion
B. More data need to be added to the conclusion
C. The conclusion is valid for the data recorded
D. The results fail to support the conclusion

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.

here's the link to your question!

explanation:

c) should be the answer.