Page 1 of 1

The states of molecules

Posted: Sun Oct 30, 2016 3:09 pm
by Josh Ku 3H
In the 1st question (part b) on the 2012 midterm it awarded points for labeling the states of the different molecules.

I was just wondering if there was any certain rules as to knowing which molecule was a solid, liquid, gas or aqueous since it wasn't stated in the question. For example, how are you supposed to know that Fe2O3 is a solid?

Re: The states of molecules  [ENDORSED]

Posted: Mon Oct 31, 2016 11:11 am
by Chem_Mod
The usual convention is to give states of each component of a reaction at conditions of room temperature and pressure unless otherwise indicated.

It is not unreasonable to be expected to know, to name a few examples, that H2O is liquid (l) or O2 is a gas (g) at room temperature. You will not be expected to know the states of every possible chemical species off the top of your head.

Thus, you should always indicate the state of each component of a reaction if known, but you will not be penalized for this in cases where states of more uncommon molecules are not given to you in the question in some way or another.