Answer:
The steps with correct mechanism are given below:
C
1) CH₄(g) + Cl(g) → CH₃(g) + HCl(g) : This is a slow step.
The rate is given as: R1 = k₁[CH₄][Cl]
2) CH₃(g) + Cl₂(g) → CH₃Cl(g) + Cl(g): This is a fast step.
The rate is given as: Rate = k₂[CH₃][Cl₂]
∴ CH₄(g) + Cl₂(g) → CH₃Cl(g) + HCl(g)
Here, the slowest step will be the rate-determining step.
The atomic mass on the periodic table represents the sum of number of protons and number of neutrons.
Atomic mass = Number of protons + number of neutrons
Hope this helps!
I think the correct answer would be negative change in enthalpy, low temperature and negative entropy. Freezing of water is an exothermic process which means heat is released to the surroundings so negative enthalpy. And this is seen in the change to a lower temperature. Entropy is negative which signifies that there is more order as water freezes.