Unit 8- Solutions Flashcards
Describe the difference between solvation and solubility.
Solvation is a process where solute particles separate and become associated with solvent molecules. Solvation also includes the creation of a solvent shell around the solute. Solvation is a kinetic process unlike solubility. Solubility is a measured amount of solute dissolved in a given amount of solvent where the rate of dissolution equals the rate of precipitation.
Describe the solution process of NaCl in water.
The crystal lattice structure has to break down the Na+ and Cl- ions; therefore, they dissociate (break apart). Water molecules surround each of those and then face different directions depending upon the charge of the ion. Then, we have the solvent shell completely forming.
What are the equations for Heat of Solution?
Delta H Solution= Delta H1+ Delta H2+ Delta H3; Delta H Solution= Delta H Lattice+ Delta H Hydration
Describe everything about Delta H1
Separating solute into individual components of solute; this is Delta H Lattice= Always +
Describe everything about Delta H2
Overcoming intermolecular forces to make room for solute; Always +
Describe everything about Delta H3
Interaction of solute/solvent to form solution; Always -
Describe everything about Delta H Hydration
Delta H2+ Delta H3= Delta H Hydration; it is ALWAYS -; it is dependent on the distance between ion and dipole (closer=stronger attraction)—> More Negative- Charge on ion (greater charge=stronger attraction)- Polarity of solvating molecule (greater magnitude= stronger attraction)
What is the formula for molarity?
M= moles solute/ Liters Solution
What is the formula for molality?
Molality= moles solute/ kg solvent
What is the formula for mole fraction?
Mole Fraction= moles solute/ moles total
What is the formula for % Mass?
% Mass= (moles solute/moles total)x100
What are the factors that affect solubility?
Temperature- Pressure- Relative structures of solute and solvent TPS (Temperature- Pressure- Structure)
What is the relationship between solubility and temperature?
In liquids, they have a direct relationship; in gases, they have an inverse relationship
Define Colloids
particles of intermediate size (1-1000nm) inside a dissolving medium.
Describe everything about Colloids
Smaller Particles= Solution; Large Particles= Suspension; Particles do not settle: particles are in their own phase independent of the medium- layers of ions/charges around the large particles prevents coagulation/precipitation. Intermediate and medium sized particles scatter light: can identify colloids using scattering light (Tyndall Effect); Examples include paint and fog; Particles are large enough to scatter light like a suspension, but small enough to not be seen with the naked eye.