Advertisements
Advertisements
प्रश्न
The rate constant of a first order reaction increases from 2 × 10−2 to 4 × 10−2 when the temperature changes from 300 K to 310 K. Calculate the energy of activation (Ea).
(log 2 = 0.301, log 3 = 0.4771, log 4 = 0.6021)
Advertisements
उत्तर
According to the Arrhenius equation,
k=Ae(−Ea/RT)
From this, we get
`"log"k_2/k_1=E_a/(2.303R)((T_2-T_1)/(T_1T_2))`
We are given that
Initial temperature, T1=300 K
Final temperature, T2=310 K
Rate constant at initial temperature, k1=2×10−2
Rate constant at final temperature, k2=4×10−2
Gas constant, R=8.314 J K−1 mol−1
Substituting the values, we get
`"log"((4xx10^(-2))/(2xx10^(-2)))=E_a/(2.303xx8.314)((310-300)/(300xx310))`
`therefore " activation energy of the reaction, "E_a=(log2xx2.303xx8.314xx300xx310)/10`
`=535985.94" J mol"^(-1)`
`=535.98" kJ mol"^(-1)`
संबंधित प्रश्न
Explain a graphical method to determine activation energy of a reaction.
(b) Rate constant ‘k’ of a reaction varies with temperature ‘T’ according to the equation:
`logk=logA-E_a/2.303R(1/T)`
Where Ea is the activation energy. When a graph is plotted for `logk Vs. 1/T` a straight line with a slope of −4250 K is obtained. Calculate ‘Ea’ for the reaction.(R = 8.314 JK−1 mol−1)
The rate constant of a first order reaction increases from 4 × 10−2 to 8 × 10−2 when the temperature changes from 27°C to 37°C. Calculate the energy of activation (Ea). (log 2 = 0.301, log 3 = 0.4771, log 4 = 0.6021)
What will be the effect of temperature on rate constant?
Calculate activation energy for a reaction of which rate constant becomes four times when temperature changes from 30 °C to 50 °C. (Given R = 8.314 JK−1 mol−1).
Explain the following terms :
Half life period of a reaction (t1/2)
Oxygen is available in plenty in air yet fuels do not burn by themselves at room temperature. Explain.
The rate constant for a reaction is 1.5 × 10–7 sec–1 at 50°C. What is the value of activation energy?
A schematic plot of ln Keq versus inverse of temperature for a reaction is shown below
The reaction must be:
What happens to the rate constant k and activation energy Ea as the temperature of a chemical reaction is increased? Justify.
