1 / 34

Make a list of ten things that have water in them.

Interest Grabber continued. Section 2-2. DO NOW. Make a list of ten things that have water in them. DO NOW. Let’s discuss your list …. Did your lists contain some of the same things?. Did anything on the other list surprise you?.

gwidon
Download Presentation

Make a list of ten things that have water in them.

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Interest Grabber continued Section 2-2 DO NOW Make a list of ten things that have water in them.

  2. DO NOW • Let’s discuss your list … • Did your lists contain some of • the same things? • Did anything on the other list • surprise you? • Did either list contain any living • things?

  3. Properties of Water I. Facts A. 75% of Earth’s surface is water B. Cells are 70 – 95% water! C. expands when freezes 1. when in solid format is actually less dense than in liquid state

  4. II. Water Molecule A. Molecule is neutral 1. has 10 protons and 10 electrons B. Water is a polar molecule 1. water is bent - the O molecule is more negative than the H 2. Therefore water is polar because of the uneven distribution of electrons btwn the O & H atoms a. negative pole is near the O atom & positive pole is btwn the H atoms

  5. 3. has special properties a. due to ability to form multiple hydrogen bonds 1 - can be as many as 4 at a time C. Hydrogen bonds 1. Example a. molecules of water & hydrogen are held together by H-bonds 2. can be attracted to each other a. due to having both a partial positive & partial negative 3. not as strong compared to ionic or covalent

  6. D. Properties 1. cohesion a. attraction btwn molecules of the same substance b. water extremely cohesive c. water’s cohesion makes the molecules on surface to be drawn inward 1 - reason why water on a smooth surface beads up 2 - also why insects & spiders can walk on water

  7. Cohesion • Attraction between molecules of same substance • b/c of H bonding, H20 extremely cohesive • Molecules on surface of H20 drawn inward • Beading effect • Insects can walk on pond’s surface

  8. 2. Adhesion a. attraction btwn molecules of different substances b. Example 1- reading water level in graduated cylinder a - water dips in center b - 2 different molecules (water/glass) c – adhesion btwn water molecules & glass molecules is stronger than the cohesion btwn water molecules

  9. http://www.visionlearning.com/library/module_viewer.php?mid=57http://www.visionlearning.com/library/module_viewer.php?mid=57 2 – water rises higher agst the force of gravity in a narrow tube a – known as capillary action b – a force that draws water out of the roots of a plant & up the stem & leaves c – cohesion holds the water together as it rises

  10. Adhesion • Attraction between molecules of different substances • Meniscus in graduated cylinder • Water climbs slightly up glass, dips in middle • Rises against force of gravity, aka: capillary action • H20 out of roots into stems of plant

  11. The water molecule’s charge is ____ • Positive • Negative • Neutral 10 Countdown

  12. The water molecule is an example of _______ • Mixture • Solution • Compound • Suspension 10 Countdown

  13. Cohesive occurs with different molecule substances • True • False 10 Countdown

  14. Is water cohesive or adhesive? • Cohesive • Adhesive 10 Countdown

  15. When water goes from solid state to a liquid state, molecules ______ • Do nothing • Expand • Contract 10 Countdown

  16. Is water polar or nonpolar? • Polar • Nonpolar 10 Countdown

  17. Solutions & Suspensions • A. water not always pure – • often found as a mixture • 1. mixture – • material composed of two or more • elements or compounds that • are physically mixed together • but not chemically • a. examples • 1 - salt & pepper – • mixed but only physically • 2 – sugar and sand • 3 – earth’s atmospheric gases

  18. Two types of mixtures can be made with water • 1. Solution • a. a homogenous mixture of 2 or more • substances • 1 – substance breaks away then • dissolves • b. parts of a solution • 1 - Solute – substance being dissolved • 2 - Solvent – dissolving agent • http://www.northland.cc.mn.us/biology/biology1111/animations/dissolve.html

  19. Suspension • a. substance does not dissolve, but breaks into • small pieces • b. the movement of water molecules keeps the • molecules suspended • 1 – mixture of liquid & undissolved material • c. examples • 1- your body (blood, mostly water with other cell types)

  20. The water molecule is an example of _______ • Mixture • Solution • Suspension 10 Countdown

  21. The atmospheric gases on Earth are an example of _____ • Mixture • Solution 10 Countdown

  22. Making kool-aid is an example of ____ • Mixture • Solution 10 Countdown

  23. Acids, bases, & pH • A. water can react to form ions • 1. ex - forms Hydrogen ions (H+) & • Hydroxide ions (OH-) • 2. how often? • a. in pure water 1 in every 550 million

  24. pH scale • 1. used to determine the concentration • of H+ in a solution • 2. ranges from 0 to 14 • a. 7 range is neutral • b. having a pH below 7, makes it more acidic, • ‘cause it has more H+ • c. having a pH above 7 are called basic, because they have more OH- Oven cleaner Bleach Ammonia solution Increasingly Basic Soap Sea water Human blood Neutral Pure water Milk Normal rainfall Acid rain Tomato juice Increasingly Acidic Lemon juice Stomach acid

  25. 3. pure water’s pH scale is 7 • Strong acids and bases dissociate completely when • mixed w/ water

  26. C. Acids 1. forms when H+ ions are in a compound 2. increases H+ conc. (less than 7) 3. strong acids tend to have a pH value btwn 1 – 3 a. example - HCl (stomach acid)

  27. D. Bases 1. forms when the compound has OH- ions 2. reduces H+ conc. (greater than 7) 3. strong bases tend to range from 11 to 14 a. example - NaOH, lye

  28. Buffers • 1. weak acids or bases that can react with • strong acids or bases to prevent • sharp, sudden changes in pH levels

  29. Acids, Bases & pH • Buffers help to neutralize the acid or base • Examples? • Tums, Rolaids

  30. Internal pH of most cells is about 7 • a. if changes will affect the chemical • reactions that take place there • b. changes in pH can be harmful to cells • c. important to maintaining homeostasis • d. Buffers – minimize changes in • concentrations of H+ and OH- in a • solution – so cells adjust slowly

  31. Stomach acid is very acidic • True • False

  32. Buffers are needed to make an acidic a basic • True • False 10 Countdown

  33. Is bleach acidic, neutral or basic? • Acidic • Neutral • Basic 10 Countdown

  34. Is water acidic, neutral or basic? • Acidic • Neutral • Basic 10 Countdown

More Related