3. What amount of space is taken up by a rock that weighs 150 milligrams, and
has a density of 30 mg/ml? (Express your answer in Liters)

Hey there!:

Density = 30 mg/mL

Mass = 150 mg

Volume = ??

Therefore:

D = m / V

30 = 150 / V

V = 150 / 30

V = 5.0 mL

converts volume into liters :

5.0 mL / 1000 => 0.005 L or 5.0 x 10⁻³ L

Hope this helps!

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.