Week 7 Solutions

Question 1

Solution
(Definition, What do these consist of)

Answer 1

• A Homogenous mixture, meaning the composition is uniform throughout, of substances
• Solutions consist of a solvent, majority component, and a solute, minority component
• Solvent and solute particles interact thru IMF

Question 2

When are solutions aqueous

Answer 2

When the solvent is water

Question 3

What is the solution phase determined by? Give all the examples

Answer 3

Solution phase determined by the solute and solvent phase
Gaseous solution: Gas, Gas
Liquid solutions: Gas,liquid;Liquid, Liquid; Solid, liquid (Liquids are the solvent)
Solid solutions: Solid, solid

Question 4

Solubility (Definition, examples of how they can be given, solube vs insoluble)

Answer 4

Solubility: The amount of solute that will disolve in a given amount of solvent
- Mass of solute PER mass of solvent
- Mass of solute per liter of solvent (g/L)
- Moles of solute per liter of solvent (m/L)
- Solute dissolves= Soluble
- Solute does not dissolve=Insoluble

Question 5

What is mixing driven by

Answer 5

Mixing in driven by an increase in entropy

Question 6

Entropy

Answer 6

A measure of the dispersion of energy in the system

Question 7

What is IMF importance to a solution

Answer 7

IMF can contribute to or oppose solution formation. Without IMF, 2 substances would spontaneously form homogenous solutions

Question 8

What can solvents be categorized as?

Answer 8

Polar Solvents like Water
or Non polar solvents like C6H14 or CCl4 (not net dipole)

Question 9

What interactions determine whether a solution forms? (Also, when do they form and when do they not form)

Answer 9

Solvent-Solvent, solute-solute interactions, solvent-soltue interaction
Forms: If solvent-solute interactions are equal to or greater than the solvent-solvent and solute-solute interactions
Does not form: When solvent-solute interactions are less than solvent-solvent and solute-solute interactions at** HIGH DISPARITY**

Question 10

Miscibility

What is an example of a misciblility vs immiscibility in water

Answer 10

If two substances are soluble in each other in all proportions, they are said to be miscible
General rule: Like dissolves Like
Miscible: Water and an ionic compound
Immiscible: Water and grease (non-polar)

Question 11

Exothermic/Endothermic solutions
What happens to the temperature of the solution

Answer 11

Exothermic: (Hsln<0) Heat is evolved and T INCREASES
Endothermic: (H>0) Heat absorbed and T DECREASES

Question 12

How do you determine whether the enthaply of solution (delta H soln) is exo/endothermic

Answer 12

1. Seperating solute particles into constuent particles (H solute)
2. Seperating solvent particles from each other (H solvent)
3. Mixing solute and solvent particles (H mix)
4. Hess Law: H soln= H solute+H solvent+H mix

Question 13

What is the result of H solute and H solvent being endothermic
What is the result of H mixture being exothermic

Answer 13

Endo H solute, solvent: Overcome IMF between particles
Exo H mixt: form IMF between solvent and solute particles

Question 14

When do spontaneous solutions form base on the Hsoln

Answer 14

Endothermic= Spontaneous solution forms if not too positive
Zero: Yes, always forms
Exothermic: Always forms