Tight binding is not fast swapping

Science · Chemistry · ages 20-21

Name ______________________ Date ____________

What drives the chelate effect?
- Stronger metal bonds
- Entropy from freed ligands
- Heavier ligand atoms
How is the overall stability constant built from stepwise ones?
- As their product
- As their difference
- As the largest one only
The substitution rate grows when more entering group is added. Which route?
- A route with no steps
- A route that skips the metal
- An associative route
A complex is very stable yet exchanges ligands in seconds. What does this show?
- Stable complexes cannot exchange
- Tight binding and fast swapping can coexist
- Rate laws never matter
K1 is 100 and K2 is 10. Give the overall stability constant.
Answer: ______________
If the rate ignores the entering group, the route is dissociative.
Circle one: True False
A weakly bound complex must always swap ligands quickly.
Circle one: True False
Two cobalt complexes share ligands. Only one speeds up with added entering group. A student says stability constants settle which is associative. What is wrong?
- Constants describe tightness, while the rate law assigns the route
- Cobalt never substitutes
- Rate laws forbid entering groups

Answer key

For grown-ups. Fold this page away before handing over the rest.

Entropy from freed ligands · Released small ligands gain disorder, which favors binding.
As their product · Each step multiplies in, so the overall constant is the product.
An associative route · Dependence on the newcomer means it joins before or during the slow step.
Tight binding and fast swapping can coexist · Thermodynamics and kinetics answer different questions.
1000 · Multiply the steps: 100 times 10 is 1000.
True · Independence means the slow step loses a ligand before the newcomer matters.
False · Weak binding can still be kinetically inert, as the examples show.
Constants describe tightness, while the rate law assigns the route · The entering-group test decides, and only the rate data carry it.