Calculate the atom economy for making hydrogen when zinc is reacted with HCL?

So, there are two parts to this question. 

Firstly, you need to decode the words in the question and transform this into an equation. 

From chemical knowledge, you know: acid + metal --> salt + hydrogen 

So now: HCL + Zn --> ZnCl2 + H2 .... then we balance this to give: 2HCL + Zn --> ZnCl2 + H2 

Secondly, we need to recall the atom economy equation (Mr of desired product / Mr sum of all products  x 100) i.e. what you need/everything produced  x 100  

Desired product Mr i.e. of H2 is: 1 x 2 = 2

All products Mr i.e. ZnCl2 + H2 is: 65 + (2 x 35.5) + (1 x 2) = 138 

2/138 x100 =1.45% :)

Pooja D. GCSE Chemistry tutor, A Level Chemistry tutor, GCSE Biology ...

7 months ago

Answered by Pooja, a GCSE Chemistry tutor with MyTutor

Still stuck? Get one-to-one help from a personally interviewed subject specialist


£24 /hr

James B.

Degree: Management (Bachelors) - Bristol University

Subjects offered: Chemistry, Physics+ 2 more


“Hi there! I am currently a 2nd year Management student at the University of Bristol. I originally took Computer Science but switched to Management after 2 years of study. During my school life I was always very Science-based, studying...”

£18 /hr

Lorna P.

Degree: Veterinary Science (Bachelors) - Bristol University

Subjects offered: Chemistry, Maths+ 1 more


“Hello!  A bit about me.. I'm currently studying Veterinary Science at the University of Bristol, having previously completed a degree in Zoology at the University of Leeds. I'm a patient person and think teaching others is a very rew...”

£22 /hr

Charlotte R.

Degree: Natural Sciences (Bachelors) - Durham University

Subjects offered: Chemistry, Geography


“Hi there! I'm Charlie and I'm studying Natural Sciences at Durham University, specialising in Chemistry and Earth Sciences. At A Level I got 3 A*s in Chemistry, Geography and Maths from Bedford Modern School andat GSCE I have 12 A* gr...”

About the author

£20 /hr

Pooja D.

Degree: Medicine (Bachelors) - Birmingham University

Subjects offered: Chemistry, Science+ 6 more

-Personal Statements-
-Medical School Preparation-

“I have tutored for the past 3 years and have gathered many different ways of teaching concepts to students in a way that is easily-digestible and understandable. I like to focus on the core understanding of a subject matter and then a...”

You may also like...

Posts by Pooja

Calculate the atom economy for making hydrogen when zinc is reacted with HCL?

How do you write your statement to appeal to the requirements of different universities?

What is the difference between mitosis and meiosis?

Other GCSE Chemistry questions

Why can graphite conduct electricity but diamond can not?

How do each of ionic, covalent and metallic bonding compare?

Explain the atomic structure of an Atom?

Explain, in terms of sub-atomic particles, why the mass number of a magnesium atom is 24.

View GCSE Chemistry tutors


We use cookies to improve our service. By continuing to use this website, we'll assume that you're OK with this. Dismiss