Answer:
The first step in the free radical mechanism for the preparation of polyethylene is:
b. heating an organic peroxide to break the O-O bond
Explanation:
The preparation of ethylene occur by free radical mechanism , which occurs in three steps :
1. Chain Initiation
2. Chain propagation
3. Chain termination.
The first step i.e chain initiation require a radical. The compound are generally peroxide(O-O linkage) that produce radical is :
Benzoyl Peroxide
This compound when heated (with U.V radiation) produce two species of radicals .
(see the attached image)
These RADICALS are highly unstable and very reactive in nature.
They readily react with ethene and initiate the polymerisation.
Thus,
The first step in the free radical mechanism for the preparation of polyethylene is:
b. heating an organic peroxide to break the O-O bond
<u><em>The sequence of Polymerisations are:</em></u>
b. heating an organic peroxide to break the O-O bond
d. propagation of the free radicals
Answer:

Explanation:
There are three heat transfers involved.
heat from combustion of propane + heat gained by water + heat gained by calorimeter = 0
q₁ + q₂ + q₃ = 0
m₁ΔH + m₂C₂ΔT + C_calΔT = 0
Data:
m₁ = 2.1 g
m₂ = 280 g
Ti = 25.00 °C
T_f = 26.55 °C
Ccal = 92.3 J·°C⁻¹
Calculations:
Let's calculate the heats separately.
1. q₁
q₁ = 2.1 g × ΔH = 2.1ΔH g
2. q₂
ΔT = T_f - Ti = 26.55 °C - 25.00 °C = 1.55 °C
q₂ = 280 g × 4.184 J·°C⁻¹ × 1.55 °C = 1816 J
3. q₃
q₃ = 92.3 J·°C⁻¹ × 1.55 °C = 143.1 J
4. ΔH

Answer:
2NaClO₄ (aq) + Ni(NO₃)₂ (aq) → 2NaNO₃ (aq) + Ni(ClO₄)₂ (aq)
No reaction
Explanation:
NaClO₄ → Sodium perchlorate
Ni(NO₃)₂ → Nickel (II) nitrate
All the salts from nitrate are soluble salts
All the salts from perchlorate are soluble salts except for the KClO₄
This is an incomplete question, the image for the given question is attached below.
Answer : The wavelength of photon would be absorbed, 
Explanation :
From the given diagram of energy we conclude that,
Energy at ground state, A = 400 zJ
Energy of 2nd excited state, C = 1050 zJ
Now we have to calculate the energy of the photon.


Now we have to calculate the wavelength of the photon.
Formula used :

As, 
So, 
where,
E = energy of photon = 
= frequency of photon
h = Planck's constant = 
= wavelength of photon = ?
c = speed of light = 
Now put all the given values in the above formula, we get:


Therefore, the wavelength of photon would be absorbed, 