If a reaction mixture contains 3 moles of O2(g) with 4 moles of H2(g), which reactant is the limiting reactant and what is the mass (in grams) remaining of the reactant in excess?

Limiting reactant: H₂

Mass in grams remaining of the reactant in excess: 32 g

Explanation:

Reaction for the excersise is:  2H₂(g) + O₂(g) → 2H₂O (l)

Ratio is 2:1. We make these rules of three:

2 moles of hydrogen need to react with 1 mol of oxygen

Then 4 moles of H₂ will react with (4 .1) / 2 = 2 moles of O₂

We have 3 moles of O₂ and we need 2 moles, so the oxygen is my reagent in excess. 1 mol of O₂ remains (32 g) with no reaction.

Limiting reactant is the hydrogen, but let's verify:

1 mol of oxygen needs 2 moles of H₂ to react

Therefore, 3 moles of O₂ will react with (3 . 2) / 1 = 6 moles of H₂

We need 6 moles of H₂, but we have only 4 moles, not enough H₂

answer: the rate of diffusion increases with increase in temperature.

increase in temperature, increases the molecular/particles speed (kinetic energy. diffusion means movement of particles through the material.

generally, the heavier the particle the more it interacts with the environment and more the temperature matters. so higher temperature results in higher diffusion.