A tetrahedral complex with Br
, and CO
ligands can exist as optical isomers but not as
These can exist as optical isomers because a non-superimposable mirror image can be made.
since geometric isomers must have two of the same ligands on the same side of the transition metal, and
two of the same ligands diagonally opposite, but we are limited because this molecule doesn’t contain two
of the same ligands, then geometric isomers are impossible in this molecule.
Four structures are shown in the accompanying sketch.
Indicate whether any of these structures are
identical, whether any are geometric isomers, and whether any are optical isomers.
This exercise is virtually impossible to do without ball and stick molecular models.
(a) and (c) are
(b and d) are enantiomers; (a) (trans) and (b or d) (cis) are geometric isomers.
Disorder, Entropy, and Spontaneous Change
For each of the following reactions, indicate whether you would expect the entropy of the system to
increase or decrease.
If you cannot tell just by inspecting the equation, explain why.
OH(l) → CH
Increase; going from a liquid to a gas increases entropy.
(g) → 2NO
Increase; going from one mole of a gas to two moles of gas increases entropy.
(c) CO(g) + H
O(g) → CO
(g) + H
No change; going from two moles of gas to two moles of gas results in no change in entropy.
molecule of gas becomes larger (CO → CO
), while the other becomes smaller (H
O → H
) cancels out
the effect of increasing the size of the molecules.
2KCl(s) + 3
Increase; 3 moles of gas form.
Decrease; going from a liquid to a solid decreases the entropy.
(g) + O
(g) → 2 NO(g)
No change; going from two moles of gas to two moles of gas is no change in entropy.
(l) → N
(g) + 2H
Increase; forming three moles of gas.
(g) + H
(aq) → (NH
Decrease; going from one mole of gas to zero moles of gas.
In the manner used to describe Figure 17.3, describe the situation if the two liquids are water and
, a component of gasoline).
That is, what would you expect to find for the final condition of
I would expect there to be some mixing of the water and octane, due to an increase in entropy.
due to the very unfavorable enthalpy of solution, I would expect the mixing to be very minimal.
Three possible completions of a statement are given.
Explain what is wrong with each one, and then
complete the statement correctly.
For a process to occur spontaneously,
(a) the entropy of the system must increase.