What is the volume of 6.78 mol of hydrogen gas at STP?

151.87dm³

Explanation:

Given parameters:

Volume of hydrogen gas  = 6.78mole

Unknown:

Volume of hydrogen gas formed at STP  = ?

Solution:

To solve this problem;

   1 mole of a gas at STP  = 22.4dm³ So;

   6.78 mole of gas  = 6.78 x 22.4  = 151.87dm³

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.

i believe it is-

d.) gravity pulled particles of dust and gas together to form planets.