What does a negative number for the rate of formation of species (e.g., species A), rA = −3 mol/dm3 s, signify? What does a positive number signify? Explain.
Interpretation:
The significance of a given negative number for the rate of formation of species A with explanation is to be stated. The significance of a positive number for the rate of formation of species A with explanation is to be stated.
Concept introduction:
The rate of formation of any species is the total number of moles of the species,
The negative number for the rate of formation of species A signifies that it is present at the reactant side. The positive number for the rate of formation of species A signifies that it is present at the product side.
The given rate of formation of a species A is,
The above mentioned negative number of rate of formation of a species A,
According to the stoichiometry of the reaction, one mole of product, P is formed by the disappearance of one mole of A. As, species A is disappearing to produce the species P, thus, the numerical value of rate of formation of A possess the negative sign. Hence, negative number of rate of formation of a species A signifies that species A is present at the side of the reactant.
The positive number for rate of formation of a species A is,
The above mentioned positive number of rate of formation of a species A,
According to the stoichiometry of the reaction, one mole of product, A is formed by the disappearance of one mole of B. As, species B is disappearing to produce the species A, thus, the numerical value of rate of formation of A possess the positive sign. Hence, positive number of rate of formation of a species A signifies that species A is present at the side of the product.
The negative number for the rate of formation of species A signifies that it is present at the reactant side. The positive number for the rate of formation of species A signifies that it is present at the product side.