Unit 4 Chemistry Quiz #1

collision theory

chemical reactions can only occur if reactants collide…

-with proper orientation

-enough kinetic energy to break reactant bonds to form product bonds

dissolving

when solute particles become surrounded by solvent molecules

dilute solution

has a small amount of solute dissolved in the solvent

concentrated solution

has a large amount of solute dissolved in the solvent

dissolving ionic compounds

ion-dipole interaction

ionic compounds will only split apart and dissolve if…

-the intermolecular force is stronger than the intramolecular force

dissolving molecular compounds

polar compunds will only separate and dissolve if…

-the attraction between the polar compound + water is stronger than the attraction of the solid polar compound molecules

What are the factors that affect the role of dissolving?

1) Temperature: temperature gives the solvent particles higher kinetic energy thus collide with solute particles more.

2) Agitation (shaking/stirring): spreads out solute particles, more undissolved solute particles come into contact with solvent

3) Particle size (surface area): increased surface area allows more of solute to expose to the solvent

NOTE: smaller particles have greater total surface area

solubility

the maximum amount of the substance that can dissolve in a given amount of solvent at a given temperature

what are the factors that affect solubility?

1) Temperature: increasing solvent temperature increases the amount of energy to pull solute ions or molecules apart

2) Type of solute: different solutes have different solubility in the same substance

3) Nature of the solvent: the solubility of a substance is affected by the type of solvent (like dissolves like)

solubility of ionic compounds are affected by…

-ion size: larger ions are more soluble (weaker attraction)

-ion charge: weaker charges are more soluble

solubility of molecular compunds is affected by…

-molecular size:

small molecules = stronger solubility

large molecules = weaker solubility

solubility in water…

water can dissolve ionic or polar compunds but not non-polar compunds

ionic compounds > polar compounds > non-polar compunds

solubility curves

graph showing what mass of solute will dissolve in 100 g of water (solubility) over a range of temperatures