Uploaded August 2025 | Updated September 2026, 1 week ago
Separation of Mixtures
Dr. DeBacco
Mixture Definition
Mixtures: Combinations of two or more substances that retain their individual properties and are not chemically bonded.
They can vary in composition.
Two Types of Mixtures
Homogeneous Mixtures: Uniform composition throughout. Solutions are a common type.
Example: Saltwater, air
Heterogeneous Mixtures: Non-uniform composition, with visibly distinct components
Examples: sand and water, salad
Separation Techniques
Distillation- Uses differences in boiling points to separate components of a liquid mixture.
Commonly used for homogeneous mixtures like saltwater or ethanol-water
Filtration- Uses a physical barrier (filter) to separate solid particles from a liquid or gas in a heterogeneous mixture based on differences in particle size.
Chromatography- Separates components of a mixture (often homogeneous) based on their differing affinities for a stationary phase (a solid or liquid) and a mobile phase (a liquid or gas).
Comparison
Link to Lecture Slides: drive.google.com/file/d/1-XBVmfvsaVuYxl3YweLQifmsVmTFGWTg/view?usp=drive_link
*Due to the description character limit the full work cited for "Separation of Mixtures" can be viewed at... docs.google.com/document/d/1JZWQACca7pUov9-g0LZTKnZFzo6vp6T9/edit?usp=drive_link&ouid=104237452697237972847&rtpof=true&sd=true
Separation of Mixtures
Dr. DeBacco
Mixture Definition
Mixtures: Combinations of two or more substances that retain their individual properties and are not chemically bonded.
They can vary in composition.
Two Types of Mixtures
Homogeneous Mixtures: Uniform composition throughout. Solutions are a common type.
Example: Saltwater, air
Heterogeneous Mixtures: Non-uniform composition, with visibly distinct components
Examples: sand and water, salad
Separation Techniques
Distillation- Uses differences in boiling points to separate components of a liquid mixture.
Commonly used for homogeneous mixtures like saltwater or ethanol-water
Filtration- Uses a physical barrier (filter) to separate solid particles from a liquid or gas in a heterogeneous mixture based on differences in particle size.
Chromatography- Separates components of a mixture (often homogeneous) based on their differing affinities for a stationary phase (a solid or liquid) and a mobile phase (a liquid or gas).
Comparison
Link to Lecture Slides: drive.google.com/file/d/1-XBVmfvsaVuYxl3YweLQifmsVmTFGWTg/view?usp=drive_link
*Due to the description character limit the full work cited for "Separation of Mixtures" can be viewed at... docs.google.com/document/d/1JZWQACca7pUov9-g0LZTKnZFzo6vp6T9/edit?usp=drive_link&ouid=104237452697237972847&rtpof=true&sd=true
![Preparing Solutions Understanding pH and Water Potential
Molarity, Molality, and Normality
Use molarity when dealing with solution chemistry where volume is easy to measure.
Use molality when temperature varies or when studying boiling/freezing point changes.
Use normality when the reaction involves charge or proton transfer, and equivalents matter.
Molarity (M)
Molarity is the concentration of a solution expressed as moles of solute per liter of solution.
Formula:
đ=moles of solute /liters of solution
Key Features:
Depends on volume, which changes with temperature.
Commonly used in aqueous solutions, titrations, and equilibrium calculations.
Molality (m)
Molality (m): is the concentration expressed as moles of solute per kilogram of solvent.
Formula:
đ=moles of solute /kg of solvent
Key Features:
Depends on mass, not volume â temperatureâindependent.
Used in colligative properties (boiling point elevation, freezing point depression).
Normality (N)
Normality (N): measures concentration in equivalents per liter of solution.
Formula:
đ=đĂ(number of equivalents )
What Counts as an âEquivalentâ? Depends on the reaction type:
Acidâbase: Hâş or OHâť donated/accepted
Redox: electrons transferred
Precipitation: charge equivalents
Example: 1 M HâSOâ â 2 equivalents of Hâş â 2 N
Core Differences
Molarity: moles of solute per liter of solution
Temperatureâdependent (volume changes)
Most common in equilibrium, kinetics, and titrations
Molality: moles of solute per kilogram of solvent
Temperatureâindependent (mass does not change)
Used for colligative properties
Normality: equivalents per liter of solution
Reactionâspecific (acidâbase, redox, precipitation)
Useful when stoichiometry involves equivalents rather than moles
Preparing Solutions
Preparing solutions: Always specify if molarity is for the hydrate/salt form (ex. MgClâ¡6HâO)
Dilutions: CâVâ = CâVâ (valid for molarity in dilute aqueous solutions).
Understanding the CâVâ = CâVâ Equation
Dilution is about making a solution less concentrated by adding solvent (usually water). The equation:
đś_1 đ_1=đś_2 đ_2
Câ = initial concentration
Vâ = volume you need to take from the stock
Câ = final concentration
Vâ = final total volume after dilution
Why it works: The number of moles stays the same before and after dilution
*only the volume changes.
StepâbyâStep: How to Prepare a Diluted Solution
Identify Câ, Vâ, and Câ.
Solve for Vâ using
đ_1=(đś_2 đ_2)/đś_1
Measure Vâ of the stock solution.
Transfer to a volumetric flask.
Add solvent until you reach Vâ.
Definition of pH
pH=âlogâĄ10[H+]
Each 1âunit change in pH = 10âfold change in [H+]
Temperature Dependence
Kw increases with temperature
Neutral pH drops as temperature rises
At 37âŻÂ°C, neutral pH â 6.8
Important for interpreting physiological pH (blood â 7.4 is still alkaline relative to neutrality)
Strong Acids and Bases
Strong acids and strong bases dissociate completely in water
Examples:
HCl â Hâş + Clâť
NaOH â Naâş + OHâť
In dilute solutions: [Hâş] â initial concentration
Osmosis in Cells
Water moves from higher Ψ â lower Ψ across membranes.
If a cell is placed in a solution with lower Ψ â water leaves â plasmolysis
If placed in higher Ψ â water enters â turgor pressure increases
Pressure Potential (Ψp): The Push of Water
Pressure potential is the physical pressure exerted on water.
In turgid plant cells, Ψp is positive (cell wall pushes back).
In xylem, Ψp can be negative due to tension from transpiration.
Pressure can raise water potential, helping water move upward.
Movement Through Plant Tissues
Water potential gradients drive:
Root uptake
Xylem transport
Leaf transpiration
Water moves from soil (highest Ψ) â roots â stem â leaves â air (lowest Ψ).
Turgor Pressure and Cell Function
Turgor pressure maintains:
Leaf rigidity
Growth
Stomatal opening
Low Ψ in the environment â loss of turgor â wilting.
Water Potential and the CohesionâTension Mechanism
Transpiration creates negative pressure potential in leaves:
Water evaporates
Pulls water upward through xylem
Cohesion keeps the column intact
Adhesion helps water stick to xylem walls
This entire process is driven by Ψ gradients.
Gravity is overcome by pressure potential + solute potential + transpiration tension.
Typical Ψ values in a transpiring plant
Soil: Ψ â â0.1 MPa
Root xylem: Ψ â â0.3 MPa
Stem xylem: Ψ â â0.6 MPa
Leaf mesophyll: Ψ â â1.5 MPa
Air (dry): Ψ â â100 MPa or lower
This enormous gradient explains how water is pulled upward against gravity.
Link to Lecture Slides: https://drive.google.com/file/d/1mpj28HsfUezYR-QpF3iSDAS9juxqPJPj/view?usp=drive_link
Due to the description character limit the full work cited for Preparing Solutions Understanding pH and Water Potential can be viewed at... https://docs.google.com/document/d/1ARYz5HO1Do9joQZ0suC1PpF0xjbx3FSS/edit?usp=drive_link&ouid=104237452697237972847&rtpof=true&sd=true Preparing Solutions Understanding pH and Water Potential](https://i.ytimg.com/vi/WbINsHL1wbE/mqdefault.jpg)









