From fc048afc684a3866063b847b33bce2894f639757 Mon Sep 17 00:00:00 2001 From: Andrew Lorimer Date: Mon, 23 Jul 2018 22:29:28 +1000 Subject: [PATCH] add to solubility notes (revision of holiday homework) --- chem/water.md | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/chem/water.md b/chem/water.md index b664cb0..9635ed6 100644 --- a/chem/water.md +++ b/chem/water.md @@ -38,6 +38,7 @@ - since electrons are attracted to O, the other side of H atoms are free from -ve charge - +ve side of H atoms are attracted to -ve side of O atoms in other molecules - causes higher melting and boiling points, expansion when frozen (hexagonal structure), high latent heat, specific heat capacity, solvent properties +- hydroxyls (OH) dissolve easily in H2O due to H-bonding ## Solubility - "like dissolves like" - polar/non-polar substances @@ -48,6 +49,7 @@ - polar gases dissolve easily as well e.g. CO2 enables submarine photosynthesis - solubility is useful for living organisms (blood etc) - surfactants - polar + non-polar ends, dissolve in both oil + water +- solubility depends on polar / non-polar proportion ## Measuring solubility - heterogeneous (mixtures) or homogeneous (solutions) @@ -58,6 +60,9 @@ - more soluble at higher temperatures - solubility measured in g / 100g H2O +## Heating and cooling +- solubility $\propto$ temperature, so when substance is cooled, the solute is precipitated out into crystals + ## Crystallisation - used to isolate substances based on $\Delta$ solubility in substances - can cause saturated or supersaturated solutions (unstable) -- 2.43.2