Day 1 – Types of Solutions & Water and its Properties
Mixtures!Mixture: physical blend of two or more substances (no rxn, just dumped)
Homogeneous mixture: uniform composition
(i) also called a solution (ii) its components are NOT readily
distinguished
Examples: Coca-Cola, HCl (aq), salt water
Heterogeneous mixture: not uniform in composition (can pick them apart easily)
its components are readily distinguished (which means you CAN see them!).
Examples: trail mix, sand, this class!
Types of Mixtures: SolutionsA solution is a homogeneous mixture of two or more substances in a single phase
Solute – substance being dissolved (least amount)
Solvent – medium DOING the dissolving (greater amount)
In a solution, the solvent and the solute do not need to be in the same phase.
Any phase of matter can dissolve in any other phase of matter.
Water Molecule
www.ualr.edu/~botany/ botimages.html
Universal Solvent Because of its polar nature, water can easily dissolve many substances and is commonly known as the “Universal Solvent”
The Solution ProcessWater molecules are in continuous motion.
When a solute is added the water molecules will collide with it. The polar nature of water molecules attract the solute particles and the particles will break away.
Negative side of water molecules will surround positive cations
The Solution Process
Positive side of water molecules will surround negative anions
The Solution Process
Dissolving polar molecular compounds
Density – ice floats in water!One of the few solids
in which a solid will float in its own liquid.
Hydrogen bonding causes water molecules to arrange in a honeycomb pattern which increases the volume of the ice and makes it less dense
If the solute does dissolve in the solvent, the solute is soluble. (aq)
If it doesn’t dissolveit is insoluble. (s) Forms a precipitate
Solubility RulesUse STAAR chart to
determine whether or not a compound is soluble (aq) or insoluble (s)
Cu(NO3)2
MgCO3
NH4Cl
NaOH
Mg(OH)2
PbCrO4
Solubility RulesUse STAAR chart to
determine whether or not a compound is soluble (aq) or insoluble (s)
Na2CrO4
MgCrO4
CuCl2
MgF2
CuSO4
Hg2SO4
Predicting Products in a Double Replacement ReactionNa2SO4 + BaCl2
2Cr(NO3)3 + 3(NH4)2S
BaSO4 + 2NaCl
6(NH4)NO3 + Cr2S3
(s) (aq)
(aq) (s)
3KNO3 + FeCl3
Fe(NO3)3 +
3KCl (aq) (aq)
Since all reactants and products are soluble (aqueous), technically nothing happened.
(No Reaction)