MYTUTOR SUBJECT ANSWERS

387 views

What exactly is a mole of something?

The best way to think of a mole is the same way you would consider a dozen to be 12 but in this case a mole is 6.2 x 1023 molecules. 

You can use moles to work out the mass of a substance needed or produced in a reaction if you know the reaction equation and a simple formula (moles = mass/molar mass (Mr)). 

The molar mass of an element or compound is simply the mass of 1 mole of it in grams! So for carbon, the molar mass is 12 therefore 1 mole of carbon weighs 12 grams. 

e.g. for the formation of water from OH- and H+, one mole of hydroxide ions (OH-) and one mole of hydrogen ions (H+) react to produce 1 mole of water:

OH- + H----> H2O

...but hang on, how do 2 moles react to form only 1? Remember a mole is the number of molecules (6.2 x 1023 to be precise) so when two molecules combine, they form one molecule so only one mole of water is produced. 

I hope that helps to simplify moles but the best way to get your head around them is by practicing mole-based questions!

Thomas N. A Level Chemistry tutor, GCSE Chemistry tutor

1 year ago

Answered by Thomas, a GCSE Chemistry tutor with MyTutor


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

224 SUBJECT SPECIALISTS

£18 /hr

William M.

Degree: Chemistry (Masters) - Durham University

Subjects offered:Chemistry, Maths

Chemistry
Maths

“I am studying Chemistry at Durham University on a four year course, currently in my first year. I have always loved science and have tutored GCSE Chemistry students for the last two years, so I have experience in tutoring.”

£18 /hr

Zoe J.

Degree: Liberal Arts (Bachelors) - Exeter University

Subjects offered:Chemistry, Maths+ 1 more

Chemistry
Maths
Economics

“I am an enthusiastic first year student at Exeter university student studying Liberal Arts and majoring in Economics. ”

MyTutor guarantee

£22 /hr

Rachel H.

Degree: Physics and Astronomy with a Year Abroad (Bachelors) - Durham University

Subjects offered:Chemistry, Science+ 3 more

Chemistry
Science
Physics
Maths
German

“Hey, I'm Rachel and I'm a fourth year Physics Student at Durham University. My best subjects at school were always science and maths and really enjoyed using my knowledge to help my friends to understand the topics better, if they were...”

About the author

Thomas N.

Currently unavailable: until

Degree: Chemistry (Masters) - Bristol University

Subjects offered:Chemistry

Chemistry

“Hi my name's Tommy, I'm a first year chemistry student at the University of Bristol. I'm originally from Oxford and am achemistry and maths tutor looking to help students who could use a more in depth explanation of topics or just wan...”

MyTutor guarantee

You may also like...

Posts by Thomas

What exactly is a mole of something?

Why is phenol more reactive than benzene?

Other GCSE Chemistry questions

Explain why chloride and bromide are in the same group in the period table. Also describe the electronic structures of both.

What do I need to know about fractional distillation?

Why is a H+ ion referred to as a proton?

How many moles of Magnesium must react with excess Oxygen to produce 80g of Magnesium oxide?

View GCSE Chemistry tutors

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

mtw:mercury1:status:ok