Ggiven the reaction 4nh3(g) 5o2(g) --> 4no(g) 6h2o(g), what is the numerical value and sign in front of the change in [ammonia] over time for the rate expression of ammonia

Sign = Negative, since ammonia is a reactant.

Value = 1 / 4 (Inverse of it's coefficient in the equation)

Explanation:

4NH3(g) + 5O2(g) --> 4NO(g) + 6H2O(g)

The Reaction Rate for a given chemical reaction is the measure of the change in concentration of the reactants or the change in concentration of the products per unit time.

For a reaction of the form A+B→C

the rate can be expressed in terms of the change in concentration of any of its components;

rate = −Δ[A] / Δt

rate = − Δ[B] / Δt

rate = Δ[C] / Δt

Considering a reaction in which the coefficients are different:

A + 2B → 2D

It is clear that [B] decreases two times as rapidly as [A], so in order to avoid ambiguity when expressing the rate in terms of different components, it is customary to divide each change in concentration by the appropriate coefficient:

rate = − Δ[A] / Δt =  − Δ[B] / 2Δt= Δ[D] / 2Δt

Things to Note;

- For products, the sign is always positive and for reactants, the sign is always negative.

- The Numerical value is usually the inverse of the coefficient.

Rate Expression  of change in [ammonia] over time for the rate expression of ammonia:

Sign = Negative, since ammonia is a reactant.

Value = 1 / 4 (Inverse of it's coefficient in the equation)

hurricanes form when warm, moist air from the ocean surface quickly rises into the atmosphere and forms storm clouds and rain. when the clouds are formed, heat is released which warms the cool air in the upper regions of the atmosphere so that the cycle can continue. which two phases of the water cycle are repeated in this process?