How do I go about finding the mass of precipitate that forms from a solution mixture? All I'm given is the volume, molarity, and formula for two elements.
2006-10-07 20:14:05 · 4 answers · asked by Jason He 2 in Science & Mathematics ➔ Chemistry
ASSUMING that all of the reactant form product (big assumption) then the mass of the products can be found thus:
A + B ==> AB
moles AB = limiting reactant moles x molar ratio from Rx
Mass of AB = moles AB x Formula Weight (AKA Molecular Mass) of AB
Hope this helps
Ken
2006-10-07 20:24:54 · answer #1 · answered by Ken B 3 · 0⤊ 0⤋
Is this a problem for homework or is this a lab question?
If it is a homework problem then it must ask you for theoretical yield. You have to know the reaction equation. You find out by looking at the numbers in front of the molecules to see how many moles of products will be formed from a certain number of moles of reactant. Then, from the volume and molarity of the reactant, you calculate the moles of reactant. You convert that to the moles of the precipitate product. Then from the molecular formula of the product you calculate using the periodic table the molecular weight. Then you use the calculated number of moles of precipitated product to convert to weight of precipitate.
If this is a question for a lab then the yield is not theoretical because of all the lab errors. So the best way to find out the mass of the precipitate is to remove the precipitate by putting it in the centrifuge and get it out (ask your teacher how). If this is a high school lab then you probably don't have the equipment. So the best way is to weigh the reaction tube before putting anything in it. Then you react and get the precipitate. Then you try to remove as much liquid as possible, then reweigh the tube to see how much heavier it is.
2006-10-07 20:30:20 · answer #2 · answered by imtrustworthy 2 · 0⤊ 0⤋
First you must know which ions form precipitate, e.g. Barium and Sulphate.
If the molarity is given in xx Mol/dm3, find the molarity by concentratiion times volume , e.g. xx mol/dm3 X yy dm3
After finding the molarity of each ions and the ions that participate in the reaction, finding the mass by multiply the molarity of the particular ions with its relative atomic mass. E.g. Ar of Barium X molarity + Ar of Sulphur and 4 oxygen times molarity.
2006-10-07 20:22:42 · answer #3 · answered by CaiZ.StarGazer 2 · 0⤊ 0⤋
Relate............
2006-10-07 20:43:52 · answer #4 · answered by ag_iitkgp 7 · 0⤊ 1⤋