Day 1 – Types of Solutions & Water and its Properties

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)