Answer: (a) K *[A][B]^2
(b) The answer is B
Explanation:
A)
Step1:A+B<--> C (fast)
Step2: B+C→D(slow)
Rate depends on slowest step.
so,
rate = k' [B][C] ...eqn 1
But C is intermediate.so use step 1
Since 1st step is an equilibrium,
Kc = [C] /[A][B]
so,
[C] = Kc [A][B] ...eqn 2
put eqn 2 in eqn 1
rate = k' *[B] * Kc [A][B]
= k'Kc*[A][B]^2
= K *[A][B]^2 {writing k'Kc = K}
Answer: K *[A][B]^2
B)
Answer is B
Since rate depends on slowest step.
if slowest step is:
X2Y2+Z2→X2Y2Z+Z
then only,
rate= k[X2Y2][Z2]
Answer: B
Radioactive decay is expressed by the following formula:
![N_{t} = N_{0} e^{-lambda * t}](https://tex.z-dn.net/?f=%20N_%7Bt%7D%20%3D%20%20N_%7B0%7D%20%20e%5E%7B-lambda%20%2A%20t%7D%20%20%20)
N₀ is the initial number of undecayed atoms.
Nt is the number of undecayed atoms remaining after time t
λ is the decay constant.
The relationship between λ and the half life time t1/2 is:
λ =
![\frac{0.693}{ t_{1/2} }](https://tex.z-dn.net/?f=%20%5Cfrac%7B0.693%7D%7B%20t_%7B1%2F2%7D%20%7D%20)
= 0.693 / 5.27 = 0.1315
![y^{-1}](https://tex.z-dn.net/?f=%20y%5E%7B-1%7D%20)
Taking natural logs for both sides of the decay expression:
ln Nt = ln N₀ - λ t
ln Nt = ln 199 - (0.1315 x 20)
= 5.293 - 2.63 = 2.66
From which:
Nt = 14.29 g
2 would be the correct answer
Answer:
The energy of a photon depends on the frequency of the emission.
Explanation:
E = hν
where E is the energy of a photon, ν is the frequency of photon and h is Planck’s constant.
Energy of a photon is quantized and is directly proportional to the frequency of the emission.
Quantized energy of a photon explained the photoelectric effect. It was proven that light not has wave nature but particle nature as well. This later gave rise to wave particle duality of light waves.