3.10 Solubility

Solubility describes:

The extent to which a solute will dissolve into a solvent to from a solution

If a lot of the solute can dissolve it can be described as:

Highly soluble

If very little of the solute dissolves it would be described as:

Slightly (sparingly) soluble

If none of the solute can dissolve it would be:

Insoluble

Water is a ______ solvent

Common

Why is water a common solvent?

It has the ability to dissolve many different substances

When a solution has water as the solvent the solution is referred to as an:

Aqueous solution

Is water a good solvent?

Yes

Why is water a good solvent?

It is a highly polar molecule

Why is water a highly polar molecule?

It has 2 sets of lone pairs on the highly electronegative oxygen atom

The fact that water has 2 sets of lone pairs on the highly electronegative oxygen atom means that electrons are:

Pulled towards the oxygen atoms

If electrons are pulled towards the oxygen atoms, what happens to the hydrogen atoms?

Have partial positive charge

Molecular geometry of water:

Bent or angular

Bond angle of water:

104.5 degrees

What gives water a bent or angular molecular geometry and a bond angle of 104.5 degrees?

Lone pairs

What happens to ions when an ionic solid is dissolved into water?

Become hydrated

The process where the water molecules surround the ions to dissolve them

Hydration

When water molecules surround the ions they orient themselves so that:

The partially positive ends of the water molecule are closest to the negative ions and the partially negative end of the water molecule is closest to the positive ion.

The attraction between water and ionic solid is called:

Ion-dipole

Can water dissolved non-ionic substances?

Yes

What part of acetic acid is water attracted to?

Polar part

Can acetic acid form hydrogen bond with water?

Yes

Which part of acetic acid can form hydrogen bond with water?

-O-H

What allows acetic acid to dissolve in water?

Hydrogen bond between -O-H of acetic acid and water

When dissolved in water, does acetic acid break apart?

No

Does the hydrogen ion in acetic acid ionize in water?

Partially

Do most molecules in acetic acid dissociate in water?

No

Can all substances dissolve in water?

No

Memory aid for determining solubility:

Like dissolves like

“Like dissolves like” refers to the:

Types of intermolecular forces present in a sample

Substances dissolve when:

They have similar IMFs to the solvent

Substances are unlikely to dissolve when:

They have IMFs that differ from the solvent

Steps that must occur in order for a solution to form:

The solute and solvent particles must separate and then come back together

Energy is required/released when separating solute or solvent particles

Required

Energy is required/released when bringing solute and solvent particles back together

Released

The amount of energy needed for separating solute, separating solvent, and bringing solute and solvent back together depends on:

IMFs of the materials

The stronger the IMFs of the solute and solvent, the more/less energy will be involved in creating a solution

More

Polar substances will dissolve into:

Polar solvents

Nonpolar substances will dissolve into:

Nonpolar solvents

Nonpolar substances do not dissolve into:

Polar solvents

Polar substances do not dissolve into:

Nonpolar solvents

Why can’t nonpolar substances dissolve into polar solvents and polar substances into nonpolar solvents?

There is not enough energy released in the last step to negate the energy needed for the first two steps

When two substances can mix together they are said to be:

Miscible

Example of two miscible substances:

Vinegar and water

When two substances cannot mix together they are said to be:

Immiscible

Example of two immiscible substances:

Oil and water