Limiting and Excess Reactants in Redox

[susan__t]

Homework Statement

Suppose 1.00g of Mn Reacts with an excess of 6.00M HCl, how many grams of H₂ gas is produced?
What volume hydrogen gas is produced by this reaction?

Homework Equations

density of hydrogen gas is 0.08988g/L
conditions: 0 degrees celsius, 1 atm pressure

The Attempt at a Solution

First I wrote the reaction out

2Mn +6HCl -> 2MnCl₃ +3H₂

Then this is where I ran into some confusion. Does the 6.00M solution have any effect on the amount of hydrogen produced? I assumed it did not and then went on to find the moles of Mn ( 0.0182 mol) and used the molar ratio of 2:3 to find out the moles of hydrogen gas (0.0273 mol).

I then determined the grams of hydrogen gas and then used a comparison ratio between it and the density of hydrogen gas to find the volume which I determined to be 0.612L.

I just require some verification, from what I remember the limiting reactant is what determines the amount of moles produced

 

[Borek]

You are OK being wrong

Calculations are correct, but I doubt you will be able to oxidize Mn to Mn³⁺ with hydrochloric acid.

 

[Blueshift5]

in a reaction. In this case, the limiting reactant would be Mn since it is the reactant with the smaller amount (1.00g compared to the excess of HCl). Therefore, the amount of H2 gas produced would be determined by the amount of Mn present, and the excess HCl would not affect the amount of H2 gas produced. Your calculations and reasoning seem correct. It is important to remember that the limiting reactant is the one that is completely consumed in the reaction, while the excess reactant is left over. In this case, the excess HCl would not have any effect on the amount of H2 gas produced, as you correctly determined. Good job on your calculations and understanding of limiting and excess reactants in redox reactions. Keep up the good work!