Stoichiometry
Stoichiometry
Out[]=
Before running a reaction the necessary amount of all reactants must be determined. The process of determining those amounts for a given reaction is known as stoichiometry.
Phosphorus pentachloride, , is a common Lewis acid.
P
Cl
5
Out[]=
Let’s consider the reaction of 0.275 grams of solid phosphorous, , with 500 milliliters of gaseous chlorine, , to form solid at standard temperature and pressure. What is the limiting reactant and the theoretical yield of ?
P
4
Cl
2
P
Cl
5
P
Cl
5
Start by balancing the chemical reaction:
rxn=ReactionBalance["P4(s)+Cl2(g)->PCl5(s)"]
Out[]=
ChemicalReaction
Store the stoichiometric coefficients:
react=rxn["ReactantCounts"]prod=rxn["ProductCounts"]
Out[]=
1,10
Out[]=
4
Store the amount of into a assuming an uncertainty of ± 0.001 g in the measurement:
P
4
p4=ChemicalInstance,Quantity[Around[0.275,0.001],"Grams"]
Out[]=
ChemicalInstance,
Determine the phase and density of at standard temperature and pressure:
Cl
2
Out[]=
Gas,
Store the density and amount of into a assuming an uncertainty of ± 1 mL in the measurement:
Cl
2
cl2=ChemicalInstance,<|"Volume"Quantity[Around[500,1],"Milliters"],"Density"["Density"]|>
Out[]=
ChemicalInstance,Volume,Density
Define a function to compute the mole ratio:
In[]:=
moleRatio[instance_]:=With[{moles=instance["Amount"]},{instance["Formula"],UnitConvert[moles/react[instance["Chemical"]],"Millimoles"]}];
Compute the mole ratios. The smallest ratio indicates the limiting reactant:
Dataset[Map[moleRatio,{p4,cl2}]]
Out[]=
Use the limiting reactant, , to compute the theoretical yield of in grams:
P
4
P
Cl
5
ChemicalConvertChemicalInstance,p4["Amount"]*prodreact,"Grams"
Out[]=
ChemicalInstance,
Out[]=