Guide to Stoichiometry

Lead (II) and Silver Nitrate

by James Nguyen


Is the measurement and calculation of the amounts of reactants and products in chemical reactions.

Type of Reaction

Single Replacement

Balanced Equation

You have to balance it out.
Pb (s) + 2AgNO3 (aq) -------> Pb(NO3)2 (aq) + 2Ag (s)

IUPAC name and Molar Mass for each Reactant and Product

Lead and Silver Nitrate -------> Lead (II) Nitrate and Silver

207.2 g + 169.8722 g -------> 331.208 g + 107.8682

(the masses are on the periodic table)
Big image

Mole to Mole Conversions

You have to know how to convert moles of A to Moles of B. You do that by using the Coeffiecients (other wise known as your Molar Ratio) from the Balanced Equation. *must have balanced equation*

11.30mol Pb|1mol Pb(NO3) = 11.30 mol Pb(NO3)2
------------------|1mol Pb

12.1mol Ag|2mol AgNO3 = 12.1 mol AgNO3
----------------|2mol Ag

You dig it? :P

Mass to Mass Conversions

To get from grams of A to grams of B it takes 2 steps. First you use the Molar Mass to convert it to moles. Then you do your mole to mole conversion, and molar mass to get back to grams.

7.17g Pb|1mol Pb|1mol Pb(NO3)2|331.208g Pb(NO3)2 = 11.5g Pb(NO3)2
------------|207.2g Pb|1mol Pb_____ |1mol Pb(NO3)2

Limiting and Excess

You use the Mass to Mass Conversion on each of your reactants. You have to convert them to the same product. (you should use the solid) The smaller one is your limiting reactant and the larger one is your excess reactant. Imagine making a peanut butter and jelly sandwich. You have your peanut butter,your jelly,and of course the bread. Once you use all of the jelly you can't make anymore pb&j's because it would just be peanut butter. Therefore jelly is your limiting reactant.

That would be quite some jam.

Theoretical Yield

It is the most you can form with the reactants you have.It should be the smaller number from the step before. My theoretical yield was 5.47 g Ag.

Percent Yield

It is the actual yield,which is usually given to you,divided by the theoretical yield. Then you multiply it by 100. The percent yield was
x 100 = 163%
Still need help?

If you still don't get it maybe this video can help.