You would do M divided by V= D and the answer is 0.0284
Explanation:
The partial pressure of an individual gas is equal to the total pressure of the mixture multiplied by the mole fraction of the gas.
Total pressure = 2atm
Mole Fraction = number of moles / total number of moles
Neon
Mole Fraction = 4.46 / 7.35 = 0.607
Partial Pressure = 0.607 * 2 = 1.214 atm
Argon
Mole Fraction = 0.74 / 7.35 = 0.101
Partial Pressure = 0.101 * 2 = 0.202 atm
Xenon
Mole Fraction = 2.15 / 7.35 = 0.293
Partial Pressure = 0.293 * 2 = 0.586 atm
Answer: It takes 3.120 seconds for the concentration of A to decrease from 0.860 M to 0.260 M.
Explanation:
Integrated rate law for second order kinetics is given by:
k = rate constant = 
= initial concentration = 0.860 M
a= concentration left after time t = 0.260 M

Thus it takes 3.120 seconds for the concentration of A to decrease from 0.860 M to 0.260 M.
Energy is not created or destroyed due to the law of Conservation of Energy. Hope this helps!
A polyatomic ion.
Examples: Sulfate, Sulfite, Nitrate, Nitrite...