4.Properties of Solutions

What is Adhesion

💧 What Is Adhesion? Definition:

Adhesion is the attraction between molecules of different substances.

In Water:

Water molecules also stick to other materials, especially if they are polar or charged (like glass, soil, or plant cell walls).

🧪 Example of Adhesion:

• Water climbing up the walls of a glass tube (meniscus formation).

• Water sticking to plant cell walls during capillary action.

What is Cohesion

💧 What Is Cohesion? Definition:

Cohesion is the attraction between molecules of the same substance.

In Water:

Water molecules are polar, meaning they have a slightly positive side (hydrogen) and a slightly negative side (oxygen). This polarity causes water molecules to stick to each other through hydrogen bonds.

🧪 Example of Cohesion:

• Water droplets are forming on a surface.

• Surface tension: Water striders can walk on water due to water's cohesive forces.

Polarity of Water

🔗 How Do Water Molecules Combine with Each Other? Via Hydrogen Bonding:

• The oxygen atom (slightly negative) of one water molecule attracts the hydrogen atom (slightly positive) of another water molecule.

• This hydrogen bond is not as strong as a covalent bond, but it's strong enough to create cohesion.

💡 TEAS Exam Insight:

This bonding explains:

• Why water has high surface tension

• Why it resists temperature change (high specific heat)

• Why it can move upward in plants (capillary action)

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🧠 Flashcard Questions

Front	Back
What kind of bond allows water molecules to stick together?	Hydrogen bonds.
Give an example of cohesion in water.	Surface tension causes water droplets to form.
Give an example of adhesion in water.	Meniscus in a glass tube or water climbing up plant roots.

Solute, Solvent & Solution

What is the universal solvent?

🧪 Key Terms Explained

Term	Definition	Example (Salt Water)
Solute	The substance that is being dissolved in a solution.	Salt (NaCl)
Solvent	The substance that does the dissolving — typically present in the greatest amount.	Water
Solution	A homogeneous mixture of a solute dissolved in a solvent.	Salt water (salt + water)

What is the universal solvent? - Water

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🧠 Quick Memory Tip:

"Solute gets dissolved, solvent does the dissolving → together they make a solution."

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🧠 TEAS Flashcard Questions

Front	Back
What is a solute?	The substance being dissolved (e.g., salt or sugar).
What is a solvent?	The substance doing the dissolving (e.g., water).
What is a solution?	A homogeneous mixture of solute and solvent.
In a sugar water mixture, what is the solute?	Sugar.
In a sugar water mixture, what is the solvent?	Water.
What kind of mixture is a solution: homogeneous or heterogeneous?	Homogeneous — the composition is uniform.

Hydrophilic & Hydrophobic

💧 Key Concepts from the Diagram

Property	Polar Substances	Non-Polar Substances
Solubility in Water	✅ Soluble in water	❌ Insoluble in water
Examples	Salt, sugar	Oil, fat
Water Affinity	Hydrophilic (water-loving)	Hydrophobic (water-fearing)
Polarity	Have partial charges (dipoles)	No charge separation

🧪 Definitions 🔹 Hydrophilic

• Means “water-loving”

• These are usually polar substances that dissolve well in water.

• Examples: Salt (NaCl), sugar (C₆H₁₂O₆)

🔸 Hydrophobic

• Means “water-fearing”

• These are non-polar substances that do not dissolve in water.

• Examples: Oils, fats, waxes

Molarity & Dilution & Concentration

⚗ 1. Molarity (M) 🔹 Definition:

Molarity is a measure of concentration — it tells you how many moles of solute are in 1 liter of solution.

📌 Formula: Molarity (M)=moles of soluteliters of solution\text{Molarity (M)} = \frac{\text{moles of solute}}{\text{liters of solution}}Molarity (M)=liters of solutionmoles of solute​ 🧪 Example:

If you dissolve 2 moles of NaCl in 1 liter of water, the molarity is:

M=2 moles1 L=2 MM = \frac{2 \text{ moles}}{1 \text{ L}} = 2\,MM=1 L2 moles​=2M

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🧴 2. Concentration 🔹 Definition:

Concentration refers to how much solute is present in a given amount of solvent or solution.

It can be expressed in different ways:

• Molarity (mol/L) – most common on TEAS

• Percent concentration (e.g., 5% NaCl)

• Grams per liter (g/L)

🧠 TEAS Tip:

When the exam says something like “a concentrated or dilute solution,” they’re referring to how much solute is dissolved:

• High concentration = lots of solute

• Low concentration = little solute

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💧 3. Dilution 🔹 Definition:

Dilution means adding more solvent (usually water) to a solution, which lowers its concentration but keeps the amount of solute the same.

📌 Formula: M1V1=M2V2M_1V_1 = M_2V_2M1​V1​=M2​V2​

Where:

• M1M_1M1​ = initial molarity

• V1V_1V1​ = initial volume

• M2M_2M2​ = final molarity

• V2V_2V2​ = final volume

🧪 Example:

You have 100 mL of 2 M HCl and want to dilute it to 1 M. How much total solution will you have?

(2)(100)=(1)(V2)⇒V2=200 mL(2)(100) = (1)(V_2) \Rightarrow V_2 = 200\,mL(2)(100)=(1)(V2​)⇒V2​=200mL

So, you’d add 100 mL of water to make it 200 mL total.

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🧠 Flashcard Review

Front	Back
What is the formula for molarity?	M = moles of solute / liters of solution
What happens to concentration when you dilute a solution?	It decreases.
What does the equation M₁V₁ = M₂V₂ represent?	The dilution formula
If you add water to a solution, what changes?	Volume increases, concentration decreases (solute amount stays same).
What is concentration?	The amount of solute per volume of solution.

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🧪 TEAS Exam Tips:

✅ Expect questions like:

• “What is the molarity if 0.5 moles are dissolved in 250 mL?”

• “How much water must be added to dilute a 3 M solution to 1 M?”

• “Which of these solutions is more concentrated?”

Molarity & Dilution & Concentration - Practice

Osmosis

🔹 Osmosis

✅ Definition:
A type of diffusion involving water molecules moving through a semipermeable membrane from an area of low solute concentration to high solute concentration.

✅ Key Points:

• Only for water movement.

• Moves to balance solute concentration on both sides.

• Example: Water moving into root hair cells of plants; water reabsorption in kidneys.

Tips:

Think of H2O “O” in Osmosis = Movement of water

Hypotonic and Hypertonic ? how Solutes play a role in there?

🔹 Key Definitions

Term	Meaning	Effect on cell
Hypotonic solution	Lower solute concentration outside the cell compared to inside	Water moves into the cell → Cell swells or bursts (lysis)
Hypertonic solution	Higher solute concentration outside the cell compared to inside	Water moves out of the cell → Cell shrinks (crenation)
Isotonic solution	Same solute concentration inside and outside	No net water movement → Cell stays the same size

Diffusion

Net movement (Overall Movement) of anything generally from a region of higher concentration to a region of lower concentration driven by a gradient in free energy or chemical potential. Passive Transport

Note: Osmosis talks about water, but Diffusion talks about movement of particles, not water.

🔹 Key Characteristics

✔ Passive process – does not require energy (ATP).
✔ Occurs because of random movement of particles.
✔ Continues until equilibrium is reached (equal concentration everywhere).
✔ Can happen in air, liquid, or across membranes.

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🔹 Examples in the Body

• Oxygen diffusing from alveoli (lungs) into blood capillaries.

• Carbon dioxide diffusing from blood into alveoli to be exhaled.

• Perfume scent spreading across a room.

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🔑 Quick Summary

✔ Diffusion = high → low concentration without energy.

Facilitated Diffusion & Protein Channels

🔹 Facilitated Diffusion

✅ Definition:
Facilitated diffusion is the movement of molecules across a cell membrane via transport proteins from high concentration to low concentration.

✅ Key Points:

• Passive transport – does not require energy (ATP).

• Helps large or charged molecules (like glucose, ions) cross the membrane, which cannot pass directly through the lipid bilayer.

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🔹 Protein Channels

✅ What are they?

• Transmembrane proteins that form pores or channels in the membrane.

• Allow specific molecules or ions to pass through by facilitated diffusion.

✅ Examples:

• Ion channels – for Na⁺, K⁺, Ca²⁺, Cl⁻.

• Aquaporins – special channels for water transport.

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🔑 Quick Comparison:

Simple Diffusion	Facilitated Diffusion
Molecules pass directly through membrane	Molecules pass through protein channels or carriers
For small, nonpolar molecules (O₂, CO₂)	For large, polar, or charged molecules (glucose, ions)
No protein needed	Requires transport protein
Passive	Passive

Factors Affecting Diffusion(4)

🌟 Factors Affecting Diffusion – Table

Factor	Description	Effect
Distance	The distance particles travel.	Greater distance = slower diffusion rate.
Temperature	Heat energy affecting particles.	Higher temperature = faster diffusion rate.
Solvent Characteristics	Density of the medium.	Increased density (thicker fluid) slows diffusion.
Traveling Characteristics (Mass)	Mass of the diffusing particles.	Greater mass = lower diffusion rate.
Barrier Characteristics	Membrane permeability and cell polarity.	Small, non-polar molecules pass through barriers more easily. (Note from bottom text)

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✨ Flashcard Questions

Question	Answer
How does distance affect diffusion rate?	Greater distance slows diffusion.
How does temperature affect diffusion rate?	Higher temperature increases diffusion rate.
How does solvent density affect diffusion rate?	Higher density slows diffusion rate.
How does particle mass affect diffusion rate?	Greater mass decreases diffusion rate.
What type of molecules pass through barriers easier?	Small, non-polar molecules.

Summary Tip

📝 TEAS Key:
“Diffusion is faster with high temperature, small particles, short distance, low solvent density, high concentration gradient, and large surface area.”

Active Transport

🌟 Active Transport – Explanation

Feature	Explanation
Definition	Movement of molecules from low concentration to high concentration (against the gradient).
Energy?	Requires ATP energy.
Direction?	Moves against the concentration gradient (opposite of diffusion).
Example in Image	Glucose being transported into a cell using a carrier protein and ATP.
Key Protein Type	Carrier proteins or pumps (e.g. sodium-potassium pump).

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✨ Flashcard Questions

Question	Answer
What is active transport?	Movement of molecules from low to high concentration using energy.
Does active transport require energy?	Yes, it uses ATP.
Which direction does active transport move substances?	Against the concentration gradient.
What is an example of active transport?	Sodium-potassium pump; glucose uptake in intestines.
What type of proteins are involved in active transport?	Carrier proteins or pumps.

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🔑 Extra Exam Points Missing From Image

✔ Types of Active Transport:

1. Primary Active Transport:

   • Direct use of ATP (e.g. sodium-potassium pump).

2. Secondary Active Transport (Cotransport):

   • Uses energy indirectly by coupling with another molecule moving down its gradient (e.g. glucose-sodium symport).

✔ Sodium-Potassium Pump:

• Pumps 3 Na⁺ out and 2 K⁺ into the cell.

• Maintains resting membrane potential.

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📝 TEAS Tip

🔹 Active transport = ATP needed + low → high concentration.
🔹 Diffusion/facilitated diffusion = no ATP + high → low concentration.

Acids and Bases

📝 TEAS Tip

Remember:

• Acids → donate H⁺ ions.

• Bases → accept H⁺ ions or donate OH⁻ ions.

Acid: Higher Hydrogen ion concentrations make the solution more acidic.

Alkaline: Less Hydrogen ion concentrations make the solution more Alkaline.Lower hydrogen

Neutralization Reaction

Acids

• Memory Tip: Acid names often end in “-ic”

• Common Acids:

  • Hydrochloric Acid → HCl

  • Sulfuric Acid → H₂SO₄

  • Nitric Acid → HNO₃

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Bases

• Memory Tip: Base names often end in “-oxide” or “-nate”

• Common Bases:

  • Sodium Hydroxide → NaOH

  • Calcium Carbonate → CaCO₃