Solubility

Question 1

Affected by bonding

Answer 1

• bonds in substance have to break
• bonds in solvent have to break
• new bonds have to form between the substance and solvent
• substance only dissolve if strength of are bonds formed is about same as or greater than strength of bonds broken

Question 2

Polar solvents

Answer 2

• made of polar molecules
• water bonds to each other by hydrogen bonding
• not all polar solvents can form hydrogen bonds

Question 3

Ionic substances

Answer 3

• dissolve in polar solvents
• when mixed with water ions in ionic substance are attracted to oppositely charged ends of water molecules
• ions pulled away from ionic lattice by the water molecules surrounded the ions = hydration
• some ionic substances don’t dissolve because bonding between their ions are too strong

Question 4

alcohol

Answer 4

• can dissolve in polar solvents
• polar O-H bond attracted O-H bonds in water
• hydrogen bonds form between lone pairs on delta - oxygen atoms and the delta+ hydrogen atoms
• carbon chain part of alcohol isn’t attracted to water
• more carbons less soluble

Question 5

molecules with polar bonds

Answer 5

• don’t all dissolve in water
• halogenoalkanes contain polar bonds but dipoles not strong enough to form hydrogen bonds with water
• hydrogen bonding between water molecules is stronger than the bonds that would be formed with halogenoalkanes so don’t dissolve
• form pdpd happily dissolve in polar solvents that aslo form pdpd

Question 6

non-polar substances

Answer 6

• dissolve best in non-polar solvents
• ethane have LF between their molecules so form a similar bond with non-polar solvents which tend to dissolve in them
• like dissolves like because substances with similar IMF