Based on reaction kinetics, which of the following pairs of reactions and reaction rate equations represent elementary reactions? You may choose more than one reaction.
Ti + 2Cl2 = TiCl4 Rate = k[Ti][Cl2]
2SO2 + O2 = 2SO3 Rate = k[O2][SO2]2
Na2S + CuSO4 = CuS + Na2SO4 Rate = k[CuSO4]
COCl2 = CO + Cl2 Rate = k[COCl2]
HCOOH = CO2 + H2 Rate = k[HCOOH]
Pb2+ + 2Cl- = PbCl2 Rate = k[Pb2+][Cl-]2
To determine which of the given reaction rate equations represent elementary reactions, we need to look at the stoichiometry of the reactions and the exponents of the reactants in the rate equation.
An elementary reaction is a reaction that occurs in a single step and its rate is directly proportional to the concentration of the reactants raised to the power of their stoichiometric coefficients.
Let's analyze each reaction and its corresponding rate equation:
1. Ti + 2Cl2 = TiCl4
Rate = k[Ti][Cl2]
The stoichiometry of the reaction shows that it is balanced. The exponents of the reactants in the rate equation match their stoichiometric coefficients, indicating that this reaction is an elementary reaction.
2. 2SO2 + O2 = 2SO3
Rate = k[O2][SO2]^2
In this reaction, the stoichiometry is balanced. However, the exponent of SO2 in the rate equation is 2, which is not equal to its stoichiometric coefficient. This indicates that this reaction is not an elementary reaction.
3. Na2S + CuSO4 = CuS + Na2SO4
Rate = k[CuSO4]
The stoichiometry of the reaction is balanced. However, the rate equation only includes the concentration of CuSO4 and does not include concentrations of other reactants. This indicates that this reaction is not an elementary reaction.
4. COCl2 = CO + Cl2
Rate = k[COCl2]
The stoichiometry of the reaction is balanced. The rate equation includes the concentration of COCl2 only, matching its stoichiometric coefficient. This suggests that this reaction is an elementary reaction.
5. HCOOH = CO2 + H2
Rate = k[HCOOH]
The stoichiometry of the reaction is balanced. The rate equation includes the concentration of HCOOH only, matching its stoichiometric coefficient. This suggests that this reaction is an elementary reaction.
6. Pb2+ + 2Cl- = PbCl2
Rate = k[Pb2+][Cl-]^2
In this reaction, the stoichiometry is balanced. The exponents of the reactants in the rate equation match their stoichiometric coefficients, indicating that this reaction is an elementary reaction.
Based on the analysis, the following reactions are elementary reactions:
1. Ti + 2Cl2 = TiCl4 Rate = k[Ti][Cl2]
2. COCl2 = CO + Cl2 Rate = k[COCl2]
3. HCOOH = CO2 + H2 Rate = k[HCOOH]
4. Pb2+ + 2Cl- = PbCl2 Rate = k[Pb2+][Cl-]^2