Homework Help

Zinc reacts with hydrochloric acid in a single replacement reaction. If 2.62 grams of...

user profile pic

persianimmortal | Student, Grade 10 | Valedictorian

Posted April 23, 2013 at 11:39 PM via web

dislike 1 like
Zinc reacts with hydrochloric acid in a single replacement reaction. If 2.62 grams of zinc react with 3.65 grams of hydrochloric acid, then how many grams of hydrogen are actually produced if the reaction has a 93% yield?

Tagged with science, stoichiometry.

1 Answer | Add Yours

Top Answer

user profile pic

jerichorayel | College Teacher | (Level 1) Senior Educator

Posted April 24, 2013 at 12:45 AM (Answer #1)

dislike 2 like

First, we have to make the balanced chemical equation for this reaction.

`Zn + 2 HCl -> ZnCl_2 + H_2`

Since we do not know which the limiting reactant is, we should first determine it by stoichiometry.

`2.62 grams Zn * (1 mol e Zn)/(65.38 grams Zn) * (1 mol e H_2)/(1 mol e Zn)`

`= 0.04007 mol es H_2`

 

`3.65 grams HCl * (1 mol e HCl)/(36.46 grams) * (1 mol e H_2)/(2 mol es HCl)`

`= 0.05005 mol es H_2`

 

Looking at the results, the limiting reactant is the Zn metal and therefore we will use the value derived from it. 

Theoretical amount of H2 gas formed:

`0.04007 mol es H_2 * (2.016 grams H_2)/(1 mol e H_2)`

`= 0.0808 grams of H_2 is p r oduced` -> theoretical yield

 

Percentage yield:

`percent yield = (actual yield)/(theo retical yield) * 100`

`(percent yield)/100 =(actual yield)/(theo retical yield)`

`actual yield = (93)/(100) *0.0808 grams`

actual yield = 0.0751 grams of H2 were actually produced. 

Sources:

Join to answer this question

Join a community of thousands of dedicated teachers and students.

Join eNotes