Can someone please explain the calculation questions? (1 Viewer)

jk412

New Member
^ no. Lead is in excess in the reaction, isnt it?
yes it is, you finally got something right

petermik

Member
there was excess pb nope .5 molesleft

RealiseNothing

Right, lolfuck.

Well-Known Member
i remember solid lead being 0.05 and aq lead being 0.05. can't remember the rest. I think No3 was 0.1, solid silver was 0 and aq silver was 0.1.. not too sure about the last 3 as i can't remember.

KoshX87

Member
I got 2.13, wasnt sure about units, so I just copied the one on back of periodic table for water, but instead of 4.18 i replaced with 2.13

So 2.13 x10^3 J Kg^-1 K^-1
Exactly. I have a feeling this might be in the criteria...

martin96

New Member
you got pb, pb2+ wrong. its 1:2 ratio therefore moles is doubled. so the molar concentration is 0.2 not 0.05.

superSAIyan2

Member
the question doesn't ask for molar concentration. and you cant have 0.2 moles of lead since they're is only 0.1 moles to start with

Well-Known Member
the question doesn't ask for molar concentration. and you cant have 0.2 moles of lead since they're is only 0.1 moles to start with
+1. I hate arrogant people who turn out to be wrong...

KoshX87

Member
you got pb, pb2+ wrong. its 1:2 ratio therefore moles is doubled. so the molar concentration is 0.2 not 0.05.
Firstly, it was moles not molar concentration (unless im stupid and i can't remember)
Secondly, AgNO3 was limiting as you only started with 0.1 moles of both Pb(s) and AgNO3, but they're in the 1:2 ratio, so if you wanted all the Pb(s) to react, you would need to have 0.2 moles of AgNO3, which you don't have. SO, you only use 0.05 moles of Pb(s) and 0.1 moles of AgNO3. As a result all the Silver ions are removed. Therefore at the end you're gonna have 0.05 moles of Pb(s) remaining. The NO3 isn't gonna change as it is a spectator (as mentioned before) and that's gonna have 0.1 moles final for that. The silver solid will be at 0.1 mol and the Pb2+ will be at 0.05 moles.

All of that requires just use of stoichiometrics and just some common sense. I had to use an extra writing booklet for that too cause i accidentally mixed up my answer. It just takes a bit of concentration.

martin96

New Member
whatever mr. know it all