Solution and Concentration Flashcards
What are the types of concentration expressions given?
Molarity and normality
Molality
Mole fraction
Percentage expressions
Calculations involving concentration expressions
What is a solution and what are the characteristics of a solution?
A solution is a mixture of two or more components that are homogeneous down to the molecular level. The mixture is a one-phase system.
The mixture is uniform, physically, chemically and molecularly.
In a solution on or more substances (solutes) are dissolved in another substance (solvent)
The characteristics consist of
- Solutions are transparent
- Particle size is < 1nm
- Solutions do NOT have light scattering effects
What are dispersions?
A mixture that consists of at least two phases
- External
- Internal
Molecular dispersions (solutions) are solute particles that are less than 1 nm and that are true solutions.
Colloidal dispersions are from 1nm to 500nm and examples are jelly, gels, microemulsions
Coarse dispersions are greater than 500nm and examples are suspensions, emulsions, foams and aerosols.
What is the summary info about solutions?
They are mixtures, consist of one phase, are molecularly homogenous and have a particle size less than 1nm. The characteristics are clear and transparent with no light scattering effect
What are teh concentration Expressions?
- Molarity (M, mol/L)
- Molality (m, mol/kg)
- Mole fraction (X, %)
- Percent by Weight (%w/w)
- Percent by Volume (%v/v)
- Percent weight in volume (%w/v)
- Normality (N, Eq/L)
- Osmolarity (Osmol/L)
- Osmolality (Osmol/kg)
What is molarity?
Moles of solute in 1 liter of solution “Mol/L”
What is molality?
Moles of solute in 1000g of solvent (mol/kg)
What is normality?
It is the concentration expression based on the measurements of their “ionization power” (chemical equivalent) which using Eq/L, mEq/ml, or mEq/L as the units.
1 mol of hydrogen (H+) have the “ionization power” of 1 Equivalent
Examples:
1 mol of H+, Na+, K+, NH4+ = 1 Eq
1 mol of Ca2+, Zn2+ = 2 Eq
What is Valence?
It is the ionic charge number
Therefore, the equilvaent (Eq) or teh millequivalent (mEq) of the ions is related to the number of ionic charge (valence)
What is the equation for normality?
N = M x valence
(Eq/L) = (mol/L) x valence
What is osmosis?
The passage of solvent (usually water molecules through a semi-permeable membrane that only allow solvent molecule (water) to move through.
When osmosis occurs more water tends to move from pure water side (less solute concentrated side) to the solute concentrated side,.
i.e. the flow of water is against the concentration gradient of solute and the following the concentration gradient of water.
What is the osmotic pressure?
All the aqueous solution of nonvolatile solutes that can not pass freely through the semi-permeable membrane exert an osmotic pressure.
What is the Van’t Hoff and Morse Equation for osmotic pressure?
For nonelectrolytes
II =MRT
For electrolytes:
Total particle (ion) number = iM
See sheet
What are the examples of substances that contain electrolytes?
Tap water
Lactic acid solutino
Sodium chloride solution
Hydrochloric acid solution
What is an electrolyte?
(macroscopically) : A substance whose aqueous soltuion conducts an electric currect
(microscopically) : A substance (an acid, base or salt) yields ions in aqueous solution
Positive ions (cations) negative ions (anions)
