Week 8 Solutions Flashcards
Why do endothermic and exothermic solutions happen?
Exothermic solution: The energy to Mix solute and solvent particles is GREATER than seperating solvent and solute particles
Endothermic: The energy to mix solute and solvent particles is LESS than seperating solvent and solute particles
What type of reaction is overcoming ionic bonds between oppositely charged ions?
What about the heat of hydration?
What is the equation to find deltaH soln?
Overcoming ionic bonds between oppositely charged ions: deltaH solute (ENDOTHERMIC)
Heat of hydration: Hsolvent+Hmix (EXOTHERMIC)
H soln= H solute+ H hyd
h soln= H hydration - HLATTICE
What are the 3 types of scenarios that affect temperature
H solute is less than H Hydration: H Soln is Exothermic and Temperature increases
H solute is greater than H hydration: H solution is endothermic and Temperature decreases
H solute is equal to H hydration: H soln is 0 and Temperature change is 0
What is the process in adding Sodium chloride to water (increasingly)
Addition of sodium chlooride, their ions begin to dissolve in water
As solution becomes more concentrated, Some of the sodium and chloride ions can begin to recrystallize as solid sodium chloride (rate of dissolution greater than rate of crystallization)
Then, dynamic equilibrium is established when the rate of dissolution equals rate of crystallization (=, reaction is reversible)
When are solutions stable and unstable?
Stable: Unsaturated (more solute can dissolve), saturated (no more solutes can dissolve and is at dynamic equilbirum)
Unsttable: Supersaturated (crystals may grow)
How do you calculate the amount of solute that crystallizes at a given temperature
Amount of solute of supersaturated solution-amount of solute of saturated solution
What is the effect temperature has on solids and gases in a liquid in terms of solubility?
How will a solubility curve look for each
Solubility of solids in a liquid INCREASES with increase in temperature (upwards sloping)
Solubility of gases in a liquid DECREASES with increase in temperature (downwards sloping)
Why are sodas less “fizzy” when it is in the sun/room temp
Because solubility of a gas (CO2) in a liquid decreases as temperature increases
How does solubility of a gas in a liquid change with an increase in pressure? What is a real life example?
Solubility of gases in a liquid increases when pressure is increased.
When a can is opened, bubbles form due to the decrease in P, solubility
How is the solubility of gases in a liquid related to pressure of gas?
What is Henry’s Law
Linear relationship
S Gas=kH*P gas
Solubility of gas= Henry law constant * partial Pressure of gas
Solubility
When is a solute soluble/insoluble
The Amount of solute the will dissolve in a given amount of solven. When solute dissolves in solvent=soluble; Does not dissolve in solvent=insoluble
Concentration
Equation, small vs large amount of solute, ways to express
- The concentration of a solution refers to the amount of solute in a given amount of solution
- Concentration=amount of solute/amount of solvent
- Small amount of solute=dilute
- Large amount of solute=concentrated
- Number of moles, mass, volume
Why are there multiple concentration terms
There are many different combinations of quantities for the amount of solute and solvent
What are the Different units of common concentration terms?
1. M, 2. m, 3. x, 4. mol%,
- molarity (M)= mol (solute)/L solution
- molality (m)= **mol (solute)/kg **(solvent)
- mole fraction (x)= mol (solute)/mol (total solute,solvent)
- mole percent (mol%)= mole fraction (x) times 100
- parts by mass, 2. %, 3. ppm, 4. ppb, 5. %, ppm, ppb
- parts by mass=mass solute/mass solution x multiplication factor
- Percent by mass (%)=multiplication factor = 100
- parts per million by mass (ppm)= multiplciation factor=10^6
- parts per billion by mass (ppb)= multiplication factor=10^9
- Parts per volume= volume solute/volume solution x Multiplication factor
