Do Now From the list below, select the answers to the following questions: i) diamond ii)graphite iii) iodine Iv)sodium chloride v) silicon dioxide A) which solid conducts electricity B) which solid has the lowest melting point? C)Which substance conducts electricity when molten? D) which substances are covalent network solids

A) graphite B) iodine C) sodium chlordie D) diamond, graphite, silicon dioxide

Solubility Y12 Chemistry

Vocab SOLUBILITY - How likely a solid will dissolve in a liquid SOLUTE - the dissolving solid SOLVENT - the liquid

Intermolecular Forces The forces which attract molecules to each other

Water A very polar molecule Oxygen is very electronegative and Hydrogen is NOT very electronegative O-H bond is very polar

Water The electrons involved in the bond sit very close to the oxygen atom This leaves the hydrogen atom as a ‘bare’ proton This makes for a VERY polar moleucle

Water - Hydrogen Bonding The ‘bare’ proton of the H atom is strongly attracted to a lone pair of electrons on the O atom This holds the water molecules together in clusters HYDROGEN BONDING

Dissolving For a substance to dissolve, the solute to solvent interactions must be similar or stronger than the forces within the solvent and solute.

A polar substance dissolving

A polar substance dissolving

A polar substance dissolving

A polar substance dissolving

An ionic solid dissolving

An ionic solid dissolving

An ionic solid dissolving

An ionic solid dissolving

Non-Polar dissolving non-polar Organic solvents such as cyclohexane are non polar molecules. They will dissolve other non polar substances because their intermolecular forces are similar (weak).

Why they don’t like each other Polar molecules won’t mix with non-polar. Because the polar molecules are more attracted to themselves than the non-polar molecules they tend to stick together.

Practical Page 55-57 You are NOT writing a report, we are just going to test the different solutes in the two different solvents to see which solutes are soluble. Draw a results table and then complete the questions.