Tuesday Oct 21 Objective: Work on Lab reports Checkpoint: A limestone rock has a mass of 10 grams before you put it in acid. After 20 minutes, it has a mass of 5 grams. How many grams were lost? What is the % mass lost? Homework: Finish calculations of your lab report (due today at end of class)

10 g - 5 g = 5 grams 5 g / 10 g x 100 = 50% lost

Calcium Carbonate CaCO3 Calcium Carbonate CaCO3

Lab Report Introduction How much extra CO2 are we releasing into the atmosphere? How is the contributing to global warming? How do oceans absorb the CO2 and what happens to the pH of ocean water when it does this? Explain the pH scale. What is the purpose of this lab and how does it relate to what you just wrote above? Resources: Acid oceans reading quiz, book homework, internet)

pH poster

Acidification of Coral Reefs Lab MASS BEFORE (g) MASS AFTER (g) Limestone A (in 0.25 M) Limestone B (in 0.50 M) Limestone C (in 1 M)

Lab Calculations Limestone in 0.25 M acid Limestone in 0.50 M acid Mass lost = initial mass (g) – final mass (g) % mass lost = (mass lost / initial mass) x 100 Limestone in 0.50 M acid Limestone in 1 M acid

% loss data table In this lab you will be adding different concentrations of acid (0.25 M, 0.5 M, and 1 M) to calcium carbonate (what coral reefs are made of). You will measure the % loss in mass (in grams) of calcium carbonate for each of the three acids. Make a data table for this lab. Find two other lab groups and get their data for Trials 2 and 3. Calculate the average % mass loss and put it in your data table.

Lab Report Conclusion What happened to the % loss of calcium carbonate when the acid concentration increased? Summarize your findings. What was the average % loss of calcium carbonate in 0.25 M acid, 0.50 M acid, and 1 M acid. Based on your findings, what will happen to coral reefs if we continue to release carbon dioxide into the atmosphere? Why should we care about what happens to coral reefs and the acidification of the ocean?