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Solutions, Acids & Bases. The Water Molecule. How many protons does a water molecule have? How many electrons? What is the overall charge of a water molecule?. 1 H Hydrogen 1.0079. 8 O Oxygen 15.9999. The Water Molecule. How many protons does a water molecule have? 10
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The Water Molecule • How many protons does a water molecule have? • How many electrons? • What is the overall charge of a water molecule? 1 H Hydrogen 1.0079 8 O Oxygen 15.9999
The Water Molecule • How many protons does a water molecule have? 10 • How many electrons? • What is the overall charge of a water molecule? 1 H Hydrogen 1.0079 8 O Oxygen 15.9999
The Water Molecule • How many protons does a water molecule have? 10 • How many electrons? 10 • What is the overall charge of a water molecule? 1 H Hydrogen 1.0079 8 O Oxygen 15.9999
The Water Molecule • How many protons does a water molecule have? 10 • How many electrons? 10 • What is the overall charge of a water molecule? 0 + 10 – 10 = 0 1 H Hydrogen 1.0079 8 O Oxygen 15.9999
Polarity • Draw a water molecule e- e- e- e- e- e- e- e- e- e-
Polarity • Draw Hydrogen bonds between one water molecule and another.
Polarity • Oxygen has _____ protons, while Hydrogen only has _____ proton. Oxygen’s greater attraction for electrons causes the Oxygen to have a slightly ______________ charge, while Hydrogen maintains a slightly _____________ charge. 1 H Hydrogen 1.0079 8 O Oxygen 15.9999
Polarity 1 8 • Oxygen has _____ protons, while Hydrogen only has _____ proton. Oxygen’s greater attraction for electrons causes the Oxygen to have a slightly ______________ charge, while Hydrogen maintains a slightly _____________ charge. negative positive 1 H Hydrogen 1.0079 8 O Oxygen 15.9999
Polarity • Key: Why is a water molecule polar? There is an uneven charge between the positive hydrogen and negative oxygen.
Hydrogen Bonds • In terms of a water molecule explain what a hydrogen bond is: The attraction of the positively charged hydrogenatom of one water molecule to the negatively charged oxygenof another water molecule.
Hydrogen Bonds • Cohesion: The ability for water molecules to stick to themselves.
Hydrogen Bonds • How does cohesion explain why some insects can walk on water?
Hydrogen Bonds • Adhesion: The ability for water molecules to stick to other materials.
Hydrogen Bonds • How does adhesion change the way you read this graduated cylinder? Why?
Hydrogen Bonds • What is capillary action in plants? Water clings to the inside of plant roots and climbs, just like water will climb up a paper towel if you put half of it in water.
Solutions and Suspensions • Mixture: A combination of two or more substances that are physically mixed, not chemically combined. • Example: Soil, salsa, trail mix, milk, cereal, sugar water
Solutions and Suspensions • Solutions: A mixture formed when one substance dissolves in another EVENLY. • Example: Salt water
Solutions and Suspensions • Solutions: A mixture formed when one substance dissolves in another EVENLY. • Example: Salt water • A. Solute: Substance dissolved in a solution Salt = Solute
Solutions and Suspensions • Solutions: A mixture formed when one substance dissolves in another EVENLY. • Example: Salt water • A. Solute: Substance dissolved in a solution • B. Solvent: Substance that does the dissolving Salt = Solute Water = Solvent
Solutions and Suspensions • Suspensions: A mixture of water and non-dissolved materials. Example: Blood, aerosol sprays, milk
Apply What You Know Solution or Suspension? Salt and Water Sand and Water Milk Kool-Aid Chicken Noodle Soup
Acids, Bases, and pH pH • The ______ scale is used to measure the strength of acids and bases. • Complete the table: Lemon, vinegar, soda, aspirin Sour, burns, dissolves things 1-7 H+ 7 H2O Pure Water Not acidic, not basic! Soap, baking soda, ammonia 7-14 OH- Bitter, slippery
Acids, Bases, and pH C. Buffer: Weak acids or bases that neutralize strong acids or bases. Why are buffers important? When acids and bases are added to the body, the blood “buffers” preventing a pH change.
Buffers in the Body • pH of blood MUST be between 7.35 and 7.45 • Removing CO2 from the blood helps increase the pH • Removing HCO3- from the blood helps lower the pH • Buffers (Bicarbonate) maintain this acid-base balance in the blood.
pH Lab 3 1 2 4 Each lab station is doing 2 experiments! (3 people per tray) Check assignment on back wall 7 5 6 8
pH Lab 3 1 2 4 Overview • 4 drops of each sample • Put on white scratch paper • Dip a small strip of pH paper in each sample • Compare the color to the chart • Add 4 drops cabbage juice • Color the box & record • Answer questions 7 5 6 8
General Lab Rules • Stay at your lab table unless you are the designated person to get supplies. • Read ALL DIRECTIONS CAREFULLY!!!! • Wash your trays with hot, soapy water. • Clean your lab station & push in stools. • Your lab should look cleaner than when you started! • Have fun!