1) The equilibrium constant Kc of the reaction A + B ⇄ C + D is equal to 9.
If 0.4 mol of A and 0.4 mol of B are reacted, the number of moles of D formed is:
a) 0.30
b) 0.60
c) 0.40
d) 0.36
e) 0.18

a) 0.30

Explanation:

Kc = [C] [D] / ([A] [B])

Set up an ICE table:

Plug in values and solve:

9 = x² / (0.4 − x)²

3 = x / (0.4 − x)

1.2 − 3x = x

1.2 = 4x

x = 0.3

qualitative observation deals with data that can be observed with our senses: sight, smell, touch, taste, and hearing. they do not involve measurements or numbers. for instance, colors, shapes, and textures of objects are all qualitative observations.