In the reaction #Zn + 2HCl -> ZnCl_2 + H_2#, how many moles of hydrogen will be formed when 4 moles of #HCl# are consumed?

1 Answer
Write your answer here...
Start with a one sentence answer
Then teach the underlying concepts
Don't copy without citing sources
preview
?

Answer

Write a one sentence answer...

Answer:

Explanation

Explain in detail...

Explanation:

I want someone to double check my answer

Describe your changes (optional) 200

6
Jan 14, 2016

Answer:

#"2 moles H"_2#

Explanation:

Your tool of choice here will be the mole ratio that exists between zinc metal, #"Zn"#, and hydrochloric acid, #":HCl"#, in the balanced chemical equation.

#"Zn"_text((s]) + color(red)(2)"HCl"_text((aq]) -> "ZnCl"_text(2(aq]) + "H"_text(2(g]) uarr#

You're dealing with a single replacement reaction in which zinc displaces the hydrogen from hydrochloric acid. The products of the reaction are aqueous zinc chloride and hydrogen gas.

Now, as you can see from the balance chemical equation, a #1:color(red)(2)# mole ratio exists between the two reactants.

This tells you that in order for the reaction to take place, you need to have twice as many moles of hydrochloric acid as you do of zinc metal.

http://people.springfield.k12.or.us/jim.tyser/chemcom/Resources/unit1ans.html

At the same time, you have a #color(red)(2):1# mole ratio between hydrochloric acid and hydrogen gas.

This means that the reaction will always produce half as many moles of hydrogen gas as you have moles of hydrochloric acid.

Since you know that #4# moles of hydrochloric acid are taking part in the reaction, and assuming that you have enough zinc metal so that it doesn't act as a limiting reagent, you can say that the reaction will produce

#4 color(red)(cancel(color(black)("moles HCl"))) * "1 mole H"_2/(color(red)(2)color(red)(cancel(color(black)("moles HCl")))) = color(green)("2 moles H"_2)#

Was this helpful? Let the contributor know!
1500
Trending questions
Impact of this question
14359 views around the world
You can reuse this answer
Creative Commons License