Determining Initial and Equilibrium Concentration (Help!!!)


by galaticman
Tags: concentration, determining, equilibrium, initial
galaticman
galaticman is offline
#1
Mar2-12, 01:17 AM
P: 8
1. The problem statement, all variables and given/known data
You are given the equation Fe3+ + SCN- -> FeSCN-
You are performing an experiment in which you are mixing Fe(NO3)3 and NaSCN. A table is given and I will only list the first sets of data because if i can figure out the process for the first one I can figure out the rest. The table is:

10 mL of 2.0x10-3 M Fe(NO3)3
2mL of 2.0x10-3
Total Volume of Solution: 50mL

You are asked to to calculate the initial SCN- concentration (M) as well as the equilibrium FeNCS2+ concentration (M)

I am just not sure how to go about doing that. Any help would be greatly appreciated!!!!!

NOTE: It also mentions that to assume all of the SCN- is present as FeNCS2+ but I am pretty sure that this is irrelevant and is relevant to the later part of the lab
Phys.Org News Partner Science news on Phys.org
SensaBubble: It's a bubble, but not as we know it (w/ video)
The hemihelix: Scientists discover a new shape using rubber bands (w/ video)
Microbes provide insights into evolution of human language
Borek
Borek is offline
#2
Mar2-12, 02:48 AM
Admin
Borek's Avatar
P: 22,708
So, if I understand you correctly, you take 2 mL of 2x10-3M solution of SCN-, and you dilute it up to 50 mL (other solution doesn't matter at this moment)?

How many moles of SCN- in these 2 mL? What is the concentration of the solution containing this amount of SCN- in a 50 mL volume?
galaticman
galaticman is offline
#3
Mar2-12, 03:26 AM
P: 8
Yup that is pretty much it except it is not just SCN it is NaSCN but Im not sure if that matters for the problem or not?

Borek
Borek is offline
#4
Mar2-12, 04:19 AM
Admin
Borek's Avatar
P: 22,708

Determining Initial and Equilibrium Concentration (Help!!!)


It doesn't matter - if the solution is 2x10-3 M in NaSCN, it is also 2x10-3 M in Na+ and SCN-.
galaticman
galaticman is offline
#5
Mar2-12, 12:01 PM
P: 8
Ohhhh okay I got it then! Thanks!!!!!


Register to reply

Related Discussions
Chemistry Question Solution Stochiometry And Determining The Concentration? Biology, Chemistry & Other Homework 2
Determining concentration by measuring pressure change Introductory Physics Homework 1
Finding ion concentration after determining whether precipitates will form Biology, Chemistry & Other Homework 0
[Chem] Determining Masses from Concentration Biology, Chemistry & Other Homework 1
Equilibrium Concentration Biology, Chemistry & Other Homework 1