Zn + 2HCl → ZnCl2 + H2 How many moles of hydrogen are produced from the reaction of three moles of zinc with an excess of hydrochloric acid?

Answer 1

Would it not be THREE MOLES with respect to dihydrogen?

We follow the stoichiometry...

#Zn(aq) + 2HCl(aq) rarr ZnCl_2(aq) + H_2(g)uarr#

And if 6 mol of the acid are added to 3 mol of the metal...THREE moles of dihydrogen gas should result.

How do you know that hydrogen gas is bimolecular, i.e. diatomic? In fact all of the elemental gases, well all of the ones with any chemistry, are diatomic, i.e. #H_2; O_2;F_2;N_2;Cl_2#. You simply have to know this.

What is the mass of your quantity of dihydrogen gas?

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Answer 2

Owen Ambrose

According to the balanced chemical equation:

Zn + 2HCl → ZnCl2 + H2

We see that for every mole of zinc (Zn) that reacts, one mole of hydrogen gas (H2) is produced.

Since there are 3 moles of zinc, 3 moles of hydrogen gas will be produced.

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Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.