Why did we have you determine the reaction rate using reactant consumed per unit of time instead of product formed per unit of time?

Rate of reaction can be determined in terms of concentration of reactants consumed or concentration of product formed per unit time

Explanation: For the reaction below

A ===>B

The reactant is A while the product given is B.

Reaction rate = Δ[B]/Δt = -Δ[A]/Δt

The concentration of A will decrease with time while the concentration of B will increases with time.

The negative sign in -Δ[A]/Δt is to convert the expression to positive since the change will always be negative (decreases)

we can conclude that the melting point of table salt is above room temperature (it's actually 801 deg c). the melting point of mercury must be below room temperature (- 39 deg c).