delta n

Moderators: Chem_Mod, Chem_Admin

Ekayana Sethi 2K
Posts: 47
Joined: Wed Nov 16, 2016 3:03 am
Been upvoted: 1 time

delta n

Postby Ekayana Sethi 2K » Sun Jan 21, 2018 9:00 pm

How do we calculate delta n for a given equation? Is it number of moles of the products minus the number of moles of the reactants or the opposite? and do we include solid and liquid products and reactants or just gasses? and what if delta n is 0?

Chris Pleman 3E
Posts: 51
Joined: Thu Jul 27, 2017 3:01 am
Been upvoted: 2 times

Re: delta n

Postby Chris Pleman 3E » Sun Jan 21, 2018 9:06 pm

The focus should be on the change in moles of gaseous particles, as this is will sometimes be the cause of the change in volume (which will help you solve for work). As for whether it's Ps-Rs or vice versa, it's more or less focusing on the change in the number of moles due to how the initial and final state of the system differs.

Clarisse Wikstrom 1H
Posts: 63
Joined: Fri Sep 29, 2017 7:05 am

Re: delta n

Postby Clarisse Wikstrom 1H » Sun Jan 21, 2018 9:47 pm

It is also important to note that limiting reactants may still apply to a problem. For example in question 101, you have to determine the limiting reactant and then the amount of moles in excess. You would also the have to add the moles of excess to the moles of product you calculated using the balanced equation.

Kailey Brodeur 1J
Posts: 34
Joined: Thu Jul 27, 2017 3:00 am

Re: delta n

Postby Kailey Brodeur 1J » Mon Jan 22, 2018 10:23 am

If there is a limiting reactant: delta n = (moles of gas produced + excess gas reactant remaining) - moles of gas consumed
If there is no limiting reactant: delta n = moles of gas product - moles of gas reactant

Return to “Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)”

Who is online

Users browsing this forum: No registered users and 2 guests