SOLUTIONS CHEMISTRY

Question 1

What is a solution? What are solutions composed of?

Answer 1

A homogenous mixture of 2 or more substances

In a homogenous mixture the substances included are uniform

Solutions are composed of SOLUTES and SOLVENTS

Question 2

What is a solute?

Answer 2

The substance being dissolved

Can be liquid, solid, or gas

Typically the less abundant component of the solution

Question 3

What is a solvent?

Answer 3

The substance that dissolves the solute

Can be liquid, solid, or gas

Typically the substance that is in greater abundance

Question 4

What is an aqueous solution?

Answer 4

A solution created by dissolving a solute in water

Question 5

Solutions can be classified as…

Answer 5

Saturated, unsaturated, supersaturated

Question 6

What is a saturated solution?

Answer 6

The solution contains the maximum amount of solute for the solvent at a specific temperature

Question 7

What is an unsaturated solution?

Answer 7

The solution contains less than the maximum amount of solute for the solvent at a specific temperature

Question 8

What is a supersaturated solution?

Answer 8

The solution can hold more solute than is present in the saturated solution

Heat is required for more solute to be dissolved

Will form crystals (crystallize)

Question 9

What is solvation?

Answer 9

The interaction between solute and solvent particles; the attaching of solute to solvent particles is called solvation

Solvation occurs at the surface of a solid

Question 10

What type of molecule is water? What does this mean?

Answer 10

Water is a polar molecule meaning…

It is covalently bonded with positive and negative ends

Since water is polar it interacts with ionic solids (polar molecules).

NaCl is an example of an ionic solid, the positive Na+ would bond with the negative oxygen in H2O

Question 11

What is dissociation?

Answer 11

Dissociation is the process of crystal decomposition into component ions

Dissociation is the separation of ions from each other

Dissociation can be expressed by the following formula:
NaCl (s) —H2O—> Na+(aq) + Cl-(aq)

Question 12

What is Molarity (M)?

Answer 12

Mol/L (# of moles of a substance dissolved per litre of solution)

a.k.a. How much solute and solvent are present

Also referred to as the concentration of a solution. Shown with [ ]

Question 13

What are dilutions?

Answer 13

Changing the concentration of a substance to lower the molarity

More solvent is added to dilute a solution

Solutions in a lab are of high concentration and can be diluted to any desired concentration

Question 14

Dilution equation

Answer 14

(M1)(V1) = (M2)(V2)

Initial higher concentration -> final diluted concentration

Question 15

Note: know how to do the following equations

Answer 15

Moles, Molarity, etc.,

dilution, ion concentration in mixed solutions, precipitation reactions, solubility questions.

Question 16

What factors affect the role of dissolving?

Answer 16

1. Heating
   Temperature increases the motion of the molecules
   which allows them to collide with water more often
   This increases the rate of dissolving
2. Stirring
   By stirring, we are bringing fresh solvent into contact with the solute
   This increases the rate of dissolving
3. Particle Size
   Increasing the surface area (crushing) means that there is a greater probability that the molecules will collide
   This increases the rate of dissolving

Question 17

What factors affect solubility?

Answer 17

1.
Nature of solute and solvent
Polar or nonpolar Like dissolves like
2. Temperature
Solubility generally increases as temperature increases
(solid solute)
Solubility of solutes vs temperature can be graphed. The
3. Pressure
No effect for solid and liquid solutes
For gas solutes, as pressure increases solubility increases and vice versa
curves that are generated are called solubility curves
 For all gases, solubility decreases as temperature increases

Question 18

Spectator ions and net equation

Answer 18

The ionic equation shows all the ions in the reaction
Some of the ions in the equation take no part in the reaction and are not involved in the chemical change
These ions are called spectator ions and they can be cancelled off
The resulting equation is called the Net Ionic Equation