Skip to main content
Ch.14 - Chemical Kinetics
Brown - Chemistry: The Central Science 15th Edition
Brown15th EditionChemistry: The Central ScienceISBN: 9780137542970Non è quello che usi tu?Cambia libro di testo
Tutti i libri di testoBrown 15th EditionCh.14 - Chemical KineticsProblema 47a
Capitolo 14, Problema 47a

Consider the data presented in Exercise 14.19. (a) By using appropriate graphs, determine whether the reaction is first order or second order.

Guida verificata passo dopo passo
1
Start by understanding the order of a reaction, which can be determined by analyzing how the concentration of reactants changes over time. For a first-order reaction, a plot of the natural logarithm of concentration versus time will yield a straight line. For a second-order reaction, a plot of the inverse of concentration versus time will yield a straight line.
Gather the concentration data from Exercise 14.19. You will need the initial concentration and the concentration at various time intervals.
Create a graph plotting the natural logarithm of concentration (ln[Concentration]) on the y-axis against time on the x-axis. If the data points form a straight line, the reaction is first order.
Create another graph plotting the inverse of concentration (1/[Concentration]) on the y-axis against time on the x-axis. If the data points form a straight line, the reaction is second order.
Compare the two graphs. The graph that results in a straight line indicates the order of the reaction. If the ln[Concentration] vs. time graph is linear, the reaction is first order. If the 1/[Concentration] vs. time graph is linear, the reaction is second order.

Risposta video verificata per un problema simile:

Questa soluzione video è stata consigliata dai nostri tutor come utile per risolvere questo problema.
Durata del video:
2m

Concetti chiave

Ecco i concetti essenziali che devi comprendere per rispondere correttamente alla domanda.

Reaction Order

Reaction order refers to the power to which the concentration of a reactant is raised in the rate law of a chemical reaction. It indicates how the rate of reaction depends on the concentration of reactants. A first-order reaction has a linear relationship between the concentration of one reactant and the rate, while a second-order reaction involves a squared concentration term, leading to a different graphical representation.
Video consigliato:
Percorso guidato
00:36
Average Bond Order

Rate Laws

Rate laws express the relationship between the rate of a chemical reaction and the concentration of its reactants. They are determined experimentally and can be used to identify the order of a reaction. For example, a first-order rate law is expressed as rate = k[A], while a second-order rate law can be expressed as rate = k[A]^2 or rate = k[A][B], depending on the number of reactants involved.
Video consigliato:
Percorso guidato
01:52
Rate Law Fundamentals

Graphical Analysis

Graphical analysis involves plotting data to visually interpret relationships between variables. For reaction order, specific plots can be used: a plot of concentration versus time for first-order reactions yields a straight line when plotted as ln[A] versus time, while a plot of 1/[A] versus time gives a straight line for second-order reactions. Analyzing these graphs helps determine the order of the reaction based on the linearity of the plots.
Video consigliato:
Percorso guidato
06:11
Dimensional Analysis
Pratica correlata
Domanda del libro di testo

The first-order rate constant for the decomposition of N2O5, 2 N2O5(g) → 4 NO2(g) + O2(g), at 70°C is 6.82×10-3 s-1. Suppose we start with 0.0250 mol of N2O5(g) in a volume of 2.0 L. (c) What is the half-life of N2O5 at 70°C?

1058
views
Domanda del libro di testo

The gas-phase decomposition of NO2, 2 NO2(g) → 2 NO(g) + O2(g), is studied at 383°C, giving the following data:

Time (s) [NO2] (M)

0.0 0.100

5.0 0.017

10.0 0.0090

15.0 0.0062

20.0 0.0047 

(a) Is the reaction first order or second order with respect to the concentration of NO2?

(c) Predict the reaction rates at the beginning of the reaction for initial concentrations of 0.200 M, 0.100 M, and 0.050 M NO2.

1744
views
Domanda del libro di testo

Consider the data presented in Exercise 14.19. (c) What is the half-life for the reaction?

724
views
Domanda del libro di testo

From the following data for the first-order gas-phase isomerization of CH3NC to CH3CN at 215°C, calculate the first-order rate constant and half-life for the reaction:

Time (s) Pressure CH3NC (torr)

0 502

2000 335

5000 180

8000 95.5

12,000 41.7

15,000 22.4

2
views
1
comments