solvents and solubility

Question 1

solubility of a sulte in a solvent

Answer 1

complicated balance of energy required to break bonds in the solute and solvent against energy given out making new bonds between the solute and the solvent

Question 2

ionic substances dissolving in water

Answer 2

when an ionic lattice dissolves in water, it involves breaking up the bonds in the lattice and forming new bonds between the metal ions and water molecules.

the negative ions are attracted to the delta + hydrogens on the polar water molecules and the positive ions are attracted to the delta - oxygen on the polar water molecules

Question 3

hydration of ions affected by charge density

Answer 3

the higher the charge density, the greater the hydration enthalpy (e.g. smaller ions or ions with larger charges) as the ions attract the water molecules more strongly

Question 4

solubility of simple alcohols

Answer 4

smaller alcohols are soluble in water because they can form hydrogen bonds with water. the longer the hydrocarbon chain, the less soluble the alcohol

Question 5

insolubility of compounds in water

Answer 5

compounds that cannot form hydrogen bonds with water molecules such as hologenoalkanes or non polar substances like hexane will be insoluble in water

Question 6

solubility in non-aqueous solvents

Answer 6

compounds which have similar intermolecular forces to those in the solvent will generally dissolve

Question 7

when can non-polar solutes dissolve?

Answer 7

non-polar solutes will dissolve in non-polar solvents. e.g. iodine which only has london forces between its molecules will dissolve in a non polar solvent such as hexane which also only has london forces

Question 8

why is propanone a useful solvent?

Answer 8

it has both polar and non-polar characteristics. it can form london forces with some non-polar substances such as octane with its CH3 groups. its polar C=O bond can also hydrogen bond with water