Warm-Up #8 9/25/12 Answer True or False for 1-5 2 is a weaker acid then 5. Hydrogen is present in larger concentrations in acids. Buffers help control a sudden change in pH. 12 is a stronger base than 9. Tap water is neutral.

Answer True or False for 1-5 and correct it. 2 is a weaker acid then 5. - False, Stronger Hydrogen is present in smaller concentrations in acids. - False, larger Buffers help control a sudden change in pH. - True 12 is a stronger base than 9. Tap water is neutral. - False, Pure water Look at the pH scale on the board. List 3 things that are incorrect on it.

Properties of Water and pH

What We Are Learning Essential Question: What is a solution and suspension and how does it affect our blood? Objectives Examine the properties of water. Differentiate between a solution and a suspension. Identify the differences between acids and bases

Properties of Water 1. Water is polar Charges cause a bent shape. Unequal sharing of electrons. Hydrogen bonds form between two water molecules. Positive pole is between the hydrogen atoms. (+) Oxygen atom has a slightly negative end. (-)

Water expands when it freezes Ice is less dense than liquid water. This is why ice floats.

Water resists temperature changes H2O requires more heat to raise its temperature than other liquids. H2O releases a lot of heat when it cools.

Ocean water temperatures °F Location JAN FEB MAR APR 1-15 APR 16-30 MAY 1-15 MAY 16-31 JUN 1-15 JUN 16-30 JUL 1-15 JUL 16-31 AUG 1-15 AUG 16-31 SEP 1-15 SEP 16-30 OCT 1-15 OCT 16-31 NOV DEC Kiptopeke VA 36 39 46 51 56 60 66 70 69 76 77 78 74 61 54 44 Cape Hatteras NC 49 52 58 68 72 75 79 80 55 Myrtle Beach SC 48 50 62 81 83 82 67 53

Water Has a High Heat of Vaporization It takes a lot of energy to make water evaporate. High heat of vaporization helps cool the human body.

Water Sticks to Water Cohesion (Co- means together) attraction of molecules of the same substance. Water has a high surface tension.

Water is attracted to other substances Adhesion attraction of water to different substances. Capillary action Water can creep up small tubes against gravity.

Mixtures 2 or more elements or compounds that are physically mixed together but NOT chemically bonded. Ex- Salt and Pepper The Earth’s atmosphere Sugar and sand

Solutions A mixture where everything is evenly distributed. The solvent is what the solute is dissolved in. In salt water solutions Water = solvent Salt = solute

Suspensions The material added to the liquid does not dissolve, but is suspended by the liquid molecules. Ex. tea, coffee, ice cream, OJ Blood is both a solution and a suspension. How?

pH

Essential Question: Why is water called the universal solvent and how can it help our bodies pH?

pH scale Measurement system Indicates the concentration of H+ ions and OH- ions in a solution Ranges from 0 to 14

Mathematically Speaking A decrease of 1 on the pH scale is 10 times more acidic. A decrease of 2 on the pH scale is 100 times more acidic—10 x 10 = 100.

pH scale Pure water has a pH of 7. This is neutral.

Acids Acids have a pH lower than 7. Acidic solutions have high concentrations of H+ ions and low OH- concentrations. H+ > OH- The smaller the number the stronger the acid.

Bases Have pH higher than 7. A base is a compound that produces hydroxide ions (OH-) Bases contain low H+ concentrations and high OH- concentrations H+ < OH- The higher the number the stronger the base.

Buffers Weak acids or bases that prevent sudden changes in pH. Help control pH in human body. They can release H+ if pH increases or take up H+ if pH decreases. Buffers help your body maintain homeostasis!

Everything that follows this slide is NOT part of the notes

Station 1 Each decrease of 1 on the pH scale is 10X more acidic. For example, pH3 is 100X more acidic than pH5. If the pH of a sample was 2, how many times more acidic is it than a solution with a pH of 7? If the pH of a sample was 8, how many times less acidic is it than a solution with a pH of 4?

Station 2 Your stomach acid has a pH between 1-3. An acid that strong can burn a hole in your skin. How is your stomach specially equipped to handle an acid that strong? When you vomit, your throat may burn. Why does this happen?

Station 3 Acid reflux is a disease that many people suffer from. Acid from the stomach will come up into the esophagus and cause a burning sensation (heartburn). An over the counter treatment for that is Tums. Why would you take Tums (what is it doing for you)? What does the word antacid come from?

Station 4 Liquid pH Hypothesis pH Actual Soda Milk Bleach The liquids provided are known acids and bases Copy the chart to the right Hypothesize what the pH will be Test the pH with the litmus paper Record your results

Warm-Up Label A-D on the picture Below