moles to complete the reaction

Question

I wanted to know how to step by step know how to find the number of moles required to complete a reaction.

How many moles of aluminum are required to completely react with 107mL of 6.00M H2SO4 according to the balanced chemical reaction:

2Al(s)+3H₂SO₄(aq)→Al₂(SO₄)₃(aq)+3H₂(g)

Answer 1

The first step would be to find how many moles of H₂SO₄ are in the 107 mL of 6.00M solution. The definition of molarity (M) is:

M = n (Moles of solute) / V (Volume of solution in liters)

If we multiply both sides of the equation by the volume and plug in the molarity and volume of solution, we can get the number of moles of H₂SO₄:

n_H2SO4 = (6.00 M)*(0.107 L) = 0.642 moles H₂SO₄

Next, we would need to determine how many moles of aluminum are needed to react to every mole of H₂SO₄. Looking at the left side of the balanced chemical reaction equation, we would need 2 moles of aluminum (Al(s)) for every 3 moles of sulfuric acid (H₂SO₄(aq)).

So, to find the moles of aluminum needed to completely react with the sulfuric acid, we can just multiply the moles of sulfuric acid by 2/3 as shown below:

n_Al = (2/3)*(0.642 moles H₂SO₄) = 0.428 moles aluminum