Download presentation
Presentation is loading. Please wait.
1
3.
2
Homework Finish questions on the lab paper TEST on TUESDAY!
5
Good Afternoon! FIND YOUR NEW SEAT! Warm Up: Today:
Describe a hydration shell. Explain why a molecule lacking a charge would not mix with water. What types of substances are acids? What type of substances are bases? What type of bond holds the hydrogen to the oxygen on one water molecule? Today: TEST Articles
6
Hydration Shell
7
Draw one water molecule and label. Draw one micelle and label
Draw one water molecule and label. Draw one micelle and label. Use terms: hydrophobic, hydrophilic, amphipathic
8
7th Lab Groups 1: Tahjae, Joshua, Sela, Tabatha, Sudie 2: Damani, Michaela, NiaJa, Kaitlyn 3: Sydney, Jenna, Malcolm, Carrie, Lailah 4: Shelby, Madison, Emily, Christopher 5: Sarah, Mickiya, Elisha, Devon 6: Julien, Desiree, Megan, Shantel 7: Darian, Hailey, Alexis, Kayla T.
9
5th Lab Groups 1: Trystan, Ivan, Rhiannon, Sydney 2: Kylie, Matthew, Patrick, Brandon , Christopher 3: Logan, Taylor, Adrian, Hailey, Derek 4: Lacey, Alexandria, Jasmine, Carter T. 5: Caleb, Maurice, Taiquan, Nathan, Daniele 6: Carter H., Shanice, Jaylyn, Emil, Kacine 7: Rebecca, Rashel, Damon, Sheyanne
10
Good Afternoon You will need your book today.
Place homework on your desk. Acid/Base worksheet Internet assignment Please answer the following questions in your notebook: Why is water a “polar” molecule? Distinguish between an acid and a base. We know that pure water is supposed to have a ph of 7. Why is water sometimes a little more acidic or basic than that?
11
Warm Up Questions Why is water a “polar” molecule?
Distinguish between an acid and a base. We know that pure water is supposed to have a ph of 7. Why is water sometimes a little more acidic or basic than that?
12
Good Afternoon! Warm Up: List as many facts about water as you can!
Pass forward your lab reports. I’ll collect them after the bell. If you still have questions we will talk after the notes. Today: Properties of Water notes Video (5 minutes) Class work
13
Properties of Water
14
H H O Water
15
About 2/3 of the mass of a cell is made up of water, and most of the biochemical processes of life occur in water solutions.
16
- the substance that does the dissolving. (liquid)
Solvent - the substance that does the dissolving. (liquid) Solute - the substance that is dissolved. (solid) A large number of substances will dissolve in water. Water is the Universal Solvent
17
Property Description Picture Universal Solvent A large number of substances will dissolve in water
18
One side of a water molecule is slightly negative (-) and the other side is slightly positive (+).
Polar Molecule
19
Property Description Picture Polar Molecule Hydrogens are slightly positive and oxygen is slightly negative
20
Like a magnet, the positive end of one water molecule forms a bond between the negative end of another water molecule Hydrogen Bonds
21
Covalent bonding vs. Hydrogen bonding
23
Property Description Picture
Hydrogen Bonds Bond formed from the negative end of one water molecule and the positive end of another Covalent bond- holds the oxygen to the hydrogen within the water molecule
24
Water molecules stick to each other
example: This is the reason why water is found in drops; perfect spheres. Cohesion
25
Water molecules stick to other surfaces
(water sticking to a spider web) Adhesion
26
Property Description Picture
Cohesion Adhesion Water sticking to itself Air Water sticking to other surfaces Car Surface
27
Water has the ability to “climb” structures (as in water climbing a glass tube or inside a tree)
Capillary Action
28
Property Description Picture Capillary Action Water has the ability to climb structures (trees, straw)
29
water has the ability to support small objects
water has the ability to support small objects. The hydrogen bonds between neighboring molecules cause a “film” to develop at the surface Organisms like the water strider can be seen taking advantage of this property. Surface Tension
30
Property Description Picture
Surface Tension The hydrogen bonds between water molecules cause a “film” to develop at the surface
31
Water is able to absorb a large amount of heat energy before it changes temperature.
Talk about difference in temperature between VA beach and SMS High Specific Heat
32
Large bodies of water can affect the climate.
- As a result, lakes and oceans stabilize air and land temperatures.
33
Property Description Picture Resistance to Temperature Change Water can absorb large amounts of heat energy before changing temperature
34
For most substances, solids are more dense than liquids
For most substances, solids are more dense than liquids. But the special properties of water make it less dense as a solid - ice floats on water! Solid Expansion
35
When water freezes, the water molecules line up and move farther apart !
36
Which is ice and which is water?
1
37
Property Description Picture
Solid Expansion Ice floats because as water freezes the molecules line up and move farther apart. Ice = less dense than liquid water
38
WHY Water is important to cells:
POLAR DISSOLVE 1. It’s __________ so it can ____________ lots of different substances. 2. It can _________ lots of ______ _______________________________ very much (That helps with _________________) 3. ____________________ form between water molecules so they stick together. 4.Water is an important ___________________ in many CHEMICAL REACTIONS. absorb HEAT WITHOUT changing temperature HOMEOSTASIS HYDROGEN BONDS REACTANT/PRODUCT
39
The pH scale ranges from 0 to 14.
40
So what is the pH of water?
HOH A little bit Acidic A little bit Basic = Neutral
41
Acids vs. Bases ACIDS BASES pH < 7 pH > 7
Sour taste taste bitter Lots of H+ lots of OH-
42
Water Acid gets stronger as number decreases Base gets stronger as number increases
43
Buffers Chemicals that neutralize small amounts of acids or bases
Controls pH which is important to maintaining homeostasis Minimizes shifts in pH Normal pH in humans is 6.5 – 7.5
46
Importance of Water to the Human Body
47
Why Is Water So Important?
Water is the most abundant substance in the body Average healthy adult is 45–75% water depending on: Age Percent of water declines with age Composition of fat and muscle Muscle is ~65% water Fat is 10–40% water Gender
48
Functions of Water in the Body
Polarity allows it to attract charged particles in solutions and dissolve a variety of other polar substances: Important to digestion Helps transport dissolved nutrients and other substances throughout the body Blood is composed of water and red blood cells Water allows blood to transport oxygen, nutrients, and hormones to cells Water helps transport waste products away from cells to be excreted Lubricates joints, sensitive eye tissues, mouth, and intestinal tract Provides a protective cushion, bathing certain organs with fluid Provides a structural component to cells
49
Functions of Water in the Body
Water is essential for most chemical reactions in the body (metabolism): During digestion water hydrolyzes the bonds holding together Carbohydrate molecules Protein molecules Fat molecules Water is formed when new materials are synthesized through the combination of smaller molecules. (condensation reaction)
50
Maintaining Water Balance
Fluid homeostasis Is necessary for normal reactions within the cells Is maintained by adaptation to changes in water intake and water loss Water balance Amount consumed = Amount excreted Figure 11.4
51
Sources of Body Water Largest source comes from beverages Food is an additional source Except for fats, all food contains some water Metabolic water – water generated during metabolism These sources contribute to an average daily intake of 2,550 ml (about 2 quarts)
52
Water Balance between Fluid Compartments
Body fluid is located: Intracellular – within the cells Extracellular – outside the cells Intravascular- fluid inside blood vessels Interstitial- fluid between cells Figure 11.5
55
WHAT IS MEANT HYDROPHOBICITY ?
Some of the common natural Hydrophobic materials are waxes, oil and fats. The evaluation of hydrophobicity is made through water contact angle measurements. A water droplet would be spherical so the water contact angle will be significantly high.
56
SUPER HYDROPHOBIC COATING
The process of coating the surface of a material with hydrophobic property material in order to avoid sticking of liquids on that surface. This is absolutely unique way of coating unlike conventional which shrink continuously during drying to produce low porosity films. Super hydrophobic technology makes water bounce, it stops it, rolls it off the surface.
57
WHAT IS MEANT HYDROPHILICITY ?
Hydrophilicity, also comes from the Greek word Hydro (water) and Philicity (friendship) it refers to a physical property of a material that can transiently bond with water (H2O) through hydrogen bonding. Furthermore it allows the liquid to enter the pores of a material and totally wet it. Almost all natural materials are hydrophilic in nature. The evaluation of hydrophilicity is made through water contact angle measurements. A water droplet would occupy as long surface of the hydrophilic material as possible. So the water contact angle will be significantly low.
58
Continued…. Glucose molecules have polar hydroxyl(OH) groups in them and these attract the water to them. When sugar is in a crystal the molecules are attracted to the water and go into solution. Once in solution the molecules stay in solution at least in part because they become surrounded by water molecules. This layer of water molecules surrounding another molecule is called a hydration shell.
60
How does water dissolve molecules?
This is why sweet tea doesn’t taste gritty.
62
Good Afternoon! You will need a sheet of paper and a pen/pencil for your warm up. You have a water quiz today!
72
Good Morning Lab is postponed until tomorrow. Today: pH worksheet
Water Dissociation packet
73
Good Afternoon! Warm Up: Begin writing these questions and your answers in your notebook as soon as you are seated. Why is water considered a “polar” molecule? Differentiate between cohesion and adhesion. Capillary action is made possible by what other two properties of water? Define hydrophobic and hydrophilic. Would table salt be considered hydrophobic? Today: Notes x 2! (We need to play catch up.) Video class work
74
HOH What is the pH of water? A little bit Acidic A little bit Basic
= Neutral The attraction between water molecules is so strong that sometimes a water molecule is ripped apart. Certain other molecules or chemicals can also donate H+ or OH- to water. Result = change in pH
75
What is an acid? a solution that has an excess of H+ ions.
It comes from the Latin word acidus that means "sharp" or "sour". The more H + ions, the more acidic the solution.
76
What is a base? a solution that has an excess of OH- ions.
Another word for base is alkali. Bitter taste Bases are substances that can accept hydrogen ions. Lots of –OH (hydroxide)
77
The pH Scale Each pH unit is 10 times as large as the previous one
A change of 2 pH units means 100 times more basic or acidic x10 x100
78
The pH Scale Careful measurement is important
A mistake of one pH unit means 10 times too much or too little! x10 x100
79
Why is pH important? Fish can’t live if the pH is too high or too low
Soil has to be in a certain pH range for plants to grow and stay healthy.
80
Hydrophilic vs. Hydrophobic Molecules
polar (charged) Can bond with and dissolve into water Hydrophobic: Nonpolar (uncharged) Cannot bond with or dissolve into water
81
Soap works because it is has hydrophobic and hydrophilic ends…it is amphipathic.
83
Homework Read pages 26-29 in your book for clarification
Quiz Wednesday Two days of notes Table Human body Notes from today WS we went over today Review WS you’re doing now
84
Homework Read pages 26-29 in your textbook before next class.
Study your notes QUIZ next class
Similar presentations
© 2025 SlidePlayer.com Inc.
All rights reserved.