Answer:
Physical
Explanation: Because it says "Until creamy" meaning you're changing the look, not the way it reacts with each other.
At STP, or standard temperature and pressure, 1 mol of any gas will take up 22.4 liters of space. Assuming STP, 4.5 moles of H2 will take up 100.8L.
The sand to pass through, but not the gravel. Hope this helps!
Molality is the moles of solute per kg of solvent.
Moles of NH₄Cl = 2.4 / (14 + 4 x 1 + 35.5)
= 0.0448 mole
Molality = 0.0448 / (19.4 / 1000)
= 2.31 m