Properties of Water What molecule supports all of

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Properties of Water

Properties of Water

What molecule supports all of life?

What molecule supports all of life?

Water Cycle

Water Cycle

What is a polar molecule? • Has polar bonds: • Water has polar covalent

What is a polar molecule? • Has polar bonds: • Water has polar covalent bonds • Oxygen is more electronegative than H • Electrons of covalent bonds spend more time closer to Oxygen than to H • Creates a polar molecule • O region is partially negative • H regions are partially positive • Causes the properties of water

POLAR MOLECULE – O H + H H 2 O +

POLAR MOLECULE – O H + H H 2 O +

HYDROGEN BONDS – + Water (H 2 O) + Hydrogen bond – Ammonia (NH

HYDROGEN BONDS – + Water (H 2 O) + Hydrogen bond – Ammonia (NH 3) + + +

States of Water

States of Water

How does this change when water is in different states? • Slightly positive H

How does this change when water is in different states? • Slightly positive H of 1 molecule is attracted to slightly negative O of nearby molecule creating a H bond that holds those molecules together

Water and Polarity Hydrogen bonds

Water and Polarity Hydrogen bonds

What are the Properties of Water? • • • Adhesion Cohesion Surface Tension High

What are the Properties of Water? • • • Adhesion Cohesion Surface Tension High specific heat Expands when frozen Universal solvent

1. Cohesion • Cohesion – water “sticking” to itself

1. Cohesion • Cohesion – water “sticking” to itself

1. Cohesion • Cohesion contributes to transport of water and dissolved nutrients against gravity

1. Cohesion • Cohesion contributes to transport of water and dissolved nutrients against gravity in plants

2. Adhesion is water “sticking” to something else

2. Adhesion is water “sticking” to something else

 • Cohesion is supported by Adhesion • What is Adhesion? • clinging of

• Cohesion is supported by Adhesion • What is Adhesion? • clinging of one substance to another • Adhesion of water to cell walls by those same hydrogen bonds

Adhesion vs. Cohesion

Adhesion vs. Cohesion

3. Surface Tension • How is this related to Surface Tension? • Surface tension=

3. Surface Tension • How is this related to Surface Tension? • Surface tension= how difficult it is to stretch or break the surface of a liquid

Examples of surface tension

Examples of surface tension

Benefits of properties 1 -3: • Bugs that walk on water • Bugs that

Benefits of properties 1 -3: • Bugs that walk on water • Bugs that use air bubble to breathe underwater • Leads to transport of water and its dissolved nutrients against gravity in plants • Water molecules leaving plants by evaporation cause H bonds to tug on water molecules, creating an upward force of water in the plant

Water and Temperature Hydrogen bonds

Water and Temperature Hydrogen bonds

4. High Heat Capacity a. k. a. High Specific Heat • Water’s temperature does

4. High Heat Capacity a. k. a. High Specific Heat • Water’s temperature does not change easily • Water can absorb or release a good deal of heat before its overall temperature changes.

What is specific heat? • the amount of heat that must be absorbed or

What is specific heat? • the amount of heat that must be absorbed or lost for 1 g of that substance to change its temperature by 1 °C

Evaporative Cooling

Evaporative Cooling

Benefits of having a high heat capacity: • Keeps temperatures more constant in bodies

Benefits of having a high heat capacity: • Keeps temperatures more constant in bodies of water so animals can survive better • Keeps water warm on a cool day and cool on a hot day, and in turn, cools the air around it on a hot day and heats air around it on a cool day • Keeps temperature from fluctuating greatly due to the fact that oceans cover the earth • Helps moderate Earth’s climate • Contributes to stability of temperature in lakes and ponds • Prevents land organisms for overheating

What happens to the ice?

What happens to the ice?

5. Expansion Upon Freezing • Water is less dense as a solid than as

5. Expansion Upon Freezing • Water is less dense as a solid than as a liquid • Ice Floats • Begins freezing when its molecules are no longer moving vigorously enough to break their hydrogen bonds • Becomes about 10% less dense

Hydrogen Bond angles

Hydrogen Bond angles

Benefits of water expanding upon freezing: • Fish get to survive in cold temperatures

Benefits of water expanding upon freezing: • Fish get to survive in cold temperatures • We get cold drinks

6. Universal Solvent

6. Universal Solvent

A few terms regarding solutions…

A few terms regarding solutions…

Solution

Solution

Suspension

Suspension

Colloid (This is why you should shake milk first!)

Colloid (This is why you should shake milk first!)

Why is water a versatile solvent? • Due to polarity of the ions •

Why is water a versatile solvent? • Due to polarity of the ions • Ions have mutual affinity through electrical attraction of the opposite charges • Compounds don’t have to be ionic to dissolve water • Dissolve when water molecules surround each of the solute molecules, forming hydrogen bonds with them

 • Hydrophilic – any substance that “loves” water and dissolves easily into it

• Hydrophilic – any substance that “loves” water and dissolves easily into it • Hydrophobic – any substance that “hates” or repels water and will not mix with it

Benefits of water’s solubility: • Allows the movement of solvents through cohesion • Makes

Benefits of water’s solubility: • Allows the movement of solvents through cohesion • Makes the solvent hydrophilic, benefitting cellular processes

QUIZ TIME! • The model illustrates hydrogen bonding found in water. This attraction between

QUIZ TIME! • The model illustrates hydrogen bonding found in water. This attraction between water molecules is the result of water’s • A ionic bonding. • B polar covalent bonding. • C positively charged atoms. • D negatively charged atoms.

Which property of water is displayed here?

Which property of water is displayed here?

Which property of water is displayed here?

Which property of water is displayed here?

Which property of water is displayed here?

Which property of water is displayed here?

Which property of water is displayed here?

Which property of water is displayed here?

Which property of water is displayed here?

Which property of water is displayed here?

Which property of water is displayed here?

Which property of water is displayed here?