MONDAY (12/12) TUESDAY (12/13) WEDNESDAY (12/14) THURSDAY (12/15) FRIDAY (12/16) Making Acid Rain (a lab) Quiz

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1 Homework Activities Name: Date: Period: This week, we will be using our knowledge of acids and bases and studying how acids, specifically acid rain, affect our lives and our environment. We will also end the week with a Winter Holiday Party. Have a GREAT Winter Break! See you in the new year! CLASS MONDAY (12/12) TUESDAY (12/13) WEDNESDAY (12/14) THURSDAY (12/15) FRIDAY (12/16) Practice with logs Acid Rain Video Making Acid Rain (a lab) Quiz Half Day ph lab testing common, household items to see how acidic or basic they are Lecture on Acids & Bases in the Environment - Impact of acid rain/addressing acid rain concerns Work on lab writeup Holiday Party Jigsaw Complete the ph lab write-up (p. 3-4) and it to Caroline by 8:30 AM tomorrow. Read the articles on p. 6-7 on How Acid Rain Works and answer the questions on p. 8. Write a reflection on acid rain. Write about 1.) how it is created 2.) why acid rain is a problem and how it affects us 3.) what is being done to stop the problem. Type up this reflection (should be about 1- page double-spaced) and it to Caroline by 8:30 AM tomorrow. Lab writeup due Friday at 8:30 AM (p ). STUDY FOR QUIZ TOMORROW on *solutions & concentrations *properties acids & bases *solving logs *ph, poh Make sure you your making acid rain lab writeup by Friday morning at 8:30 AM. Bring in a dish for our holiday party! Enjoy your winter holiday break!! 1

2 Warmup Practice with Logarithms 2

3 ph Lab Introduction: In this lab, we will investigate how acid and basic common household solutions are. We will be testing their strengths using two indicators ph paper and red cabbage indicator juice. Once we measure the ph of each substance, we will determine the concentration of hydrogen ions ([H+]) and hydroxide ions ([OH-]) in each solution. Materials: Beaker of Red Cabbage Juice ph paper 8 test tubes 1 test tube rack 1 pipette A cupful of each of the following solutions: water, baking soda solution, vinegar, lemon juice, dish detergent, bleach, hydrochloric acid, soda Procedure: 1.) Make sure you have gloves and goggles on! 2.) Make sure your test tubes are labeled #1-8 3.) Pour each solution into its corresponding test tube (look at data table). Fill the test tube half way. 4.) Dip the ph paper into each solution for a couple of seconds, and then take it out to observe the color change. Record the color change in your data table. 5.) Match up the color of the ph paper with the ph indicator key to see what the ph was. 6.) Next, fill the pipette with cabbage juice and drop a pipette-full amount of cabbage juice into each test tube. 7.) Observe the color change and record it in your data table. 8.) Match up the color of the solution and cabbage juice mixture with the ph indicator key. Record what the ph of the solution is in the data table. 9.) Calculate the concentration of H+ ions, poh and OH-ions. 3

4 Data & Observations The following table shows the ph measurements of each household solution. Solution # Solution ph paper color ph Cabbage juice color ph Average ph Acid, base or neutral? 1. water 2. Baking soda 3. vinegar 4. Lemon juice 5. Dish detergent 6. bleach 7. Hydrochloric acid 8. soda The following table shows the ph and poh measurements and the concentration of hydrogen and hydroxide ions in each solution. Solution # Solution Average ph poh [H+] in M [OH-] in M 1. water 2. Baking soda 3. vinegar 4. Lemon juice 5. Dish detergent 6. bleach 7. Hydrochloric acid 8. soda 4

5 Conclusion: 1.) Which solutions were acids? 2.) How did you know the solutions you listed in #1 were acids? 3.) Which solutions were bases? 4.) How did you know the solutions you listed in #3 were bases? 5.) Were there any neutral solutions? How do you know those solution(s) were neutral? 6.) What is the difference between ph and poh? What do they measure? 7.) How did you figure out the concentration of hydrogen ions present in each solution? Show your work for at least one calculation you did to figure out the hydrogen ion concentration. Type up your calculations in google or Microsoft equation. 8.) How did you figure out the concentration of hydroxide ions present in each solution? Show your work for at least one calculation you did to figure out the hydroxide ion concentration. Type up your calculations in google or Microsoft equation. 9.) Why is it important to know what the hydrogen and hydroxide ion concentrations are in solutions? What do these numbers tell us about a solution? For homework, make sure you type up the Data & Observation and Conclusion sections and it to Caroline by Tuesday 8:30 AM! 5

6 How Acid Rain Works 6

7 ACID RAIN (p. 363 in chemistry textbook) 1.) According to the article on p. 6, why does acid rain mainly occur in the Northern Hemisphere? 2.) What are some sources of acid rain? 3.) How is acid rain produced? 4.) According to article on p. 6, what is acid rain exactly? 5.) Natural precipitation has a ph of less than 7 why is this? 6.) What is the ph of normal rainwater? What chemical reaction occurs normally for the ph of rainwater to be slightly acidic? 7.) According to the chemical reactions on p. 7, what does the reaction of sulfur dioxide (SO 2 ) and sulfur trioxide (SO 3 ) with water produce? 8.) According to the chemical reactions on p. 7, what does the reaction of nitrogen dioxide (NO 2 ) with water produce? 7

8 Effects of Acid Rain 8

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12 Acid Rain Topic Summary of topic 1.) The ph of acid rain How acid rain affects the ph of normal rainwater: Effects of acid rain on fish and frogs: Effects of too much nitrogen in the water: 2.) The effects of acid rain Effect of acid rain on forests and trees: Effects of acid rain on buildings, monuments, tombstones, cars: Effects of acid rain on human health: 3.) Reducing Acid Rain Clean Air Act, 1990: Acid Rain Program s (ARP) cap and trade program: New technology and cars to fix the problem: 12

13 Making Acid Rain (a lab) Introduction: In class, we have been investigating properties of acids and bases and have been studying about the effects of acid rain on our lives. In this lab, we will generate some laboratory-scale acid rain. We will then observe the effects of this acidic solution on plant material (an apple skin), on a chemically reactive metal (magnesium, Mg), and on marble (calcium carbonate, CaCO 3 ). We will use acid-base indicators to estimate the acidity of the solution. In this lab, there will be 2 reactions that will occur. First, the hydrochloric acid (HCl) will react with sodium sulfite (Na 2 SO 3 ) to produce sulfur dioxide (a gas, SO 2 ), water and salt. See chemical equation below: 2 HCl (aq) + Na 2 SO 3 (aq) ----> SO 2 (g) + H 2 O (l) + 2NaCl (aq) Once the sulfur dioxide gas (SO 2 ) is produced, it will react with water to produce sulfurous acid (H 2 SO 3 ), which is acid rain. See chemical equation below: SO 2 (g) + H 2 O (l) H 2 SO 3 (aq) Hypothesis: Predict what you think might happen if we put acid rain on An apple peel Magnesium Marble (calcium carbonate) Materials: 1 gram of sodium sulfite (Na 2 SO 3 ) 2 test tubes 1 Ziploc bag 3 pipettes Beaker water Hydrochloric acid (HCl) water 2 apple peels, approximately 2 cm in length Red and blue litmus paper ph paper 1-cm of magnesium ribbon 2 small marble chips (calcium carbonate, CaCO 3 ) 13

14 Procedure: 1.) Make sure you have goggles and gloves on! 2.) Place a 1-g sample of sodium sulfite (Na 2 SO 3 ) in a test tube. Place the test tube inside a Ziploc bag, holding it upright from outside the bag. 3.) Carefully fill a pipette with 6 M hydrochloric acid (HCl). (Caution: 6 M HCl is corrosive. If you spill it on yourself or others, wash it off thoroughly and inform Caroline. Avoid breathing any HCl fumes). Carefully rinse off any acid left on the outside of the pipet. 4.) Without squeezing the pipette bulb, place the filled pipette inside the test tube containing sodium sulfite. Then carefully add 10 ml of water to the inside of the bag. Make sure that the distilled water does not come in contact with the hydrochloric acid or the sodium sulfite. Carefully smooth the bag to force out most of the air. Close the bag with the zip-seal strip. See the picture. 5.) Slowly squeeze the pipette bulb through the outside of the bag so that hydrochloric acid drips onto the solid sodium sulfite. Keep the test tube upright, so its contents do not spill out. Keep the bag sealed. 6.) Allow the reaction in the test tube to proceed for 1 to 2 minutes, gently tapping the test tube every few seconds. After the reaction in the test tube has stopped, gently swirl the water in the bottom of the bag for another 1 to 2 minutes. Do not swirl the water so vigorously that it mixes with the contents of the test tube. 14

15 7.) (Caution: Avoid inhaling the gas released when you open the bag). Carefully open a top corner of the bag and, using a clean dry pipette, transfer three pipettes of water from the bottom of the bag to a clean, dry test tube. Reseal the bag. Label the test tube A. 8.) Get two fresh apple skin pieces and place them on a paper towel. Add 4 to 5 drops of liquid from test tube A to the outside of one piece of apple skin. Add 4 to 5 drops of water to the second piece of apple skin. This second apple-skin sample serves as a control. After 3 minutes, observe the two apple-skin samples; record your observations. 9.) Place one drop of water each on fresh strips of red litmus paper, blue litmus paper and ph paper. Record your observations. 10.) Repeat step 8, except use solution from test tube A in place of the distilled water. Record your observations. 11.) Place a 1-cm length of magnesium ribbon in a separate clean, dry test tube. Add one pipette of solution from test tube A. Observe the reaction for 3 min. Record your observations. 12.) Add two small marble chips (calcium carbonate, CaCO 3 ) to the solution remaining in test tube A. Observe the marble chips for 3 minutes; record your observations. 13.) Dispose of all remaining solutions in a bottle provided in the classroom. DO NOT POUR IT DOWN THE SINK! 14.) Wash your hands thoroughly. 15

16 Data & Observations APPLE PEELS Observations of Apple Peel and Sulfurous Acid (Test Tube Solution A) Observations of Apple Peel and Water LITMUS PAPER & PH PAPER TEST Sulfurous Acid (Test Tube Solution A) Water Reaction with red litmus paper Reaction with blue litmus paper Reaction with ph paper What do you think the ph is? MAGNESIUM RIBBON Write down your observations of the reaction between Sulfurous Acid (Test Tube Solution A) and the magnesium ribbon: MARBLE Write down your observations of the reaction between Sulfurous Acid (Test Tube Solution A) and the marble chip (calcium carbonate CaCO 3 ): 16

17 Conclusion: 1.) Summarize how we made acid rain in this lab. Use the chemical equations in the introduction to help you. 2.) What effect did the SO 2 gas (sulfur dioxide see first chemical equation) have on the acidity of the water placed inside the bag? Support your answer by using specific observations you made and test results. 3.) Explain how this lab models the production of acid rain. How is this lab similar to what happens in the production of real-life acid rain? 4.) As you know, precipitation with a ph of less than 5.6 is defined as acid rain. How does the ph of your solution compare to this value? 5.) If a liquid similar to the solution in the plastic bag moistened a marble statute or steel building, what effect might it have? FOR HOMEWORK, TYPE UP YOUR DATA AND CONCLUSION SECTIONS AND IT TO CAROLINE BY FRIDAY AT 8:30 AM. 17