Consider this reaction:

2Cl2O5 (g)-->2Cl2(g) +5O2 (g)

At a certain temperature it obeys this rate law.

rate= (17.4 M -1 .s -1 ) [Cl2O5]2

Suppose a vessel contains Cl2O5 at a concentration of 1.46M. Calculate the concentration of Cl2O5 in the vessel .400 seconds later. You may assume no other reaction is imporant. Round your answer to 2 significant digits.

0.13 M ( 2 s.f)

Explanation:

2Cl2O5 (g)-->2Cl2(g) +5O2 (g)

rate= (17.4 M -1 .s -1 ) [Cl2O5]2

From the rte above, we can tell that our rate constant (k)  = 17.4 M -1 .s -1

The units of k tells us this is a second order reaction.

Initial Concentration  [A]o = 1.46M

Final Concentration  [A] = ?

Time = 0.400s

The integrated rate law for second order reactions is given as;

1 / [A] = (1 / [A]o) + kt

1 /  [A] = [ (1/ 1.46) + (17.4 * 0.4) ]

1 /  [A] = 0.6849 + 6.96

1 /  [A] = 7.6496

[A] = 1 / 7.6496

[A] = 0.13073 M ≈ 0.13 M ( 2 s.f)

the ideal gas law equation is as follows

pv = nrt

where p - pressure

v - volume

n - number of moles

r - universal gas constant

t - temperature

so if the pressure, volume and temperature are already known

we are left with n and r

since r is the universal gas constant that has a known fixed value then r too is known

so we are left with 'n'

once we know temperature volume and pressure

we can find the number of moles of gas present using the ideal gas law equation

this is not my own answer, this is an answer for the same question by the user blahblahmali. i do not claim ownership of this account.