The rate of reaction can be observed by watching the disappearance of a reactant or the appearance of a product over time.The reaction rate is calculated using the formula rate = Δ/Δt, where Δ is the change in product concentration during time period Δt.Rates of reaction can be measured by the production of gas over time, the change in mass over time or the formation of precipitation over time.Ĭhemistry Question Pack Passage 10 Question 59 This can be related by the equation below: Since one molecule of A and two molecules of B are consumed for every three molecules of C that are produced, the rates of disappearance and appearance of these chemical species are different but related. The rate of change of the reactants can also be used to calculate the rate of reaction as all reactants and products are equal when considering their stoichiometric relationship. The rate of reaction can be taken from a graph of time against the concentration of C where a tangent can be plotted to time and the gradient calculated to work out the rate of reaction at that exact time. This instantaneous slope, or rate, is written as:
The limit of this average rate as the time interval becomes smaller is called the rate of appearance of C at time t, and it is the slope of the curve of versus t at time t. This is the average rate of appearance of C during the time interval Δt.
The concentration of C,, is usually expressed in moles/liter.
Here, the rate of appearance of product C in time interval Δt is: The reaction rate is usually observed by watching the disappearance of a reactant or the appearance of a product within a given time period. Reaction rates are determined by observing the changes in the concentrations of reactants or products over a specific time frame.
0 kommentar(er)
