Unit 9 Stoichiometry Test Review

Vocabulary and quantitative concepts from the Unit 9 Stoichiometry test review and calculation worksheets.

Stoichiometry

The study of quantitative relationships between reactants and products in a chemical reaction.

Limiting reactant

The reactant that controls the amount of product formed and determines the amount of product that can form in a reaction.

Excess reactant

A reactant that is left over after the reaction is complete.

Coefficients

Numbers in a balanced chemical equation that indicate both the number of molecules and the number of moles of each substance.

Law of conservation of mass

The principle that the total mass of reactants equals the total mass of products.

Haber process Stoichiometry ($N_2 + 3H_2 \rightarrow 2NH_3$)

If $2\,moles$ of ammonia are produced, $3\,moles$ of hydrogen were consumed.

Molar conversion check ($KClO_3$)

For the reaction $2KClO_3 \rightarrow 2KCl + 3O_2$, $1.65\,mol\,KClO_3$ yields $2.48\,mol\,O_2$ using the molar ratio $\frac{3\,moles\,O_2}{2\,mole\,KClO_3}$.

Propane combustion yield ($C_3H_8$)

For the reaction $C_3H_8 + 5O_2 \rightarrow 3CO_2 + 4H_2O$, using $44.09\,g\,C_3H_8$ results in a theoretical yield of $132\,g\,CO_2$.

Limiting Reactant (LR) identification ($S_8$ and $Cl_2$)

In a reaction between $100.0\,g\,S_8$ and $70.0\,g\,Cl_2$, $Cl_2$ is the limiting reactant because it produces $967\,nuks$ ($0.987\,moles$) of product, which is less than the $1.559\,moles$ from $S_8$.

Theoretical yield of $S_2Cl_2$

The calculated product amount in the reaction of sulfur and chlorine, which is $133\,g$.

Excess remaining ($S_8$)

The calculation for reactant left over: $100.0\,g$ given $-$ $63.3\,g$ consumed $=$ $36.7\,g$ remaining.