At a certain temperature the equilibrium constant, Kc, equals 0.11 for the reaction:
2 ICl(g) ? I2(g) + Cl2(g).
What is the equilibrium concentration of ICl if 0.45 mol of I2 and 0.45 mol of Cl2 are initially mixed in a 2.0-L flask?

a.) 0.17 M

b.) 0.27 M

c.) 0.34 M

d.) 0.14 M

The equilibrium concentration of ICl is 0.27 M

Explanation:

We are given:

Initial moles of iodine gas = 0.45 moles

Initial moles of chlorine gas = 0.45 moles

Volume of the flask = 2.0 L

The molarity is calculated by using the equation:

Initial concentration of iodine gas =

Initial concentration of chlorine gas =

For the given chemical equation:

As, the initial moles of iodine and chlorine are given. So, the reaction will proceed backwards.

The chemical equation becomes:

Initial:         0.225      0.225

At eqllm:   0.225-x    0.225-x     2x

The expression of for above equation follows:

Putting values in above equation, we get:

Neglecting the value of x = 0.668 because equilibrium concentration cannot be greater than the initial concentration

So, equilibrium concentration of ICl = 2x = (2 × 0.135) = 0.27 M

Hence, the equilibrium concentration of ICl is 0.27 M

"record the time to complete a chemical reaction" would most likely be part of a lab procedure.

it can be observed without changing the identity of the object.

it depends on what substance you're talking about as well as many other factors. in quantum mechanics, the observation of particles affects the observers ability to measure certain properties. for example: you can know the velocity of a particle, but you can't know it's position; or you can know it's position, but not it's velocity. it's like trying to find out where a grain of sand is by throwing other grains of sand at it. once you find out where it is, it's been moved. it's also like trying to find an answer to the question of whether or not a tree falling in a forest makes a sound if nobody is there to hear it. paradoxically, the only way to find out is to be there and hear it.