CH 11 Explore Activity: Carbon Changing Costumes

In the engage activity, you saw that carbon can take the forms of CO 2 gas, solid CO 2 (dry ice) and carbonic acid (H 2 CO 3 ).

In natural systems, carbon wears many costumes and takes part in many chemical reactions During this activity, you will explore these costumes and reactions. Investigative Question: In nature, what FORMS does carbon take? In nature, what CHEMICAL REACTIONS does carbon participate in? Obtain a sketch that shows where in nature these chemical reactions happen. During the lab, you will be recording your findings in pencil on this sketch. After we debrief the lab, you will make a final draft of this labeled sketch.

Set up your lab notebook Title Investigative Questions Make a heading for each of the lab stations 1-8. Allow ½ a page for each station.

Keep these overarching questions in mind as you go through the lab stations…… 1.What carbon form is being represented? 2.Is carbon changing form? How? 3.Where on earth might I find this carbon form and this carbon form change? 4.How might 2 or more of these carbon forms and carbon reactions be related?

Station 1 DATA: Sketch bottles; describe them. DATA: Observe and record your observations. DATA: Make a graph showing what you learned about CO 2 solubility. Put CO 2 solubility on the Y-axis and temperature on the X-axis. Include labels.

Station 1 Q’s 1.What carbon forms participated in this reaction? 2.How did carbon change form? Why? 3.WHAT’S THE BIG IDEA????? (copy and answer question 8 on p. 552) 4.Show, on the diagram, where on earth this chemical reaction would occur. Include arrows to show carbon’s movement. Label with station #.

Station 2 What happens to rainwater as it percolates through rich, organic soil? (FOCUS QUESTION - discuss this with your lab mates before you begin) 1.Mix 1 spoonful of soil in 100ml of water. 2.Describe/draw what you see. 3.Put a paper filter into the funnel. Pour the soil/water mixture through the filter. 4.Describe/draw the filtrate (color, smell, clarity, etc.) Clean up after yourselves…..dirty water, used filters, used paper towels and etc. go in the big bucket. (All of this can go in the food waste container and be COMPOSTED!!)

Station 2 Q’s 1.What does percolate mean? 2.What does organic mean? 3.What form or forms of carbon are present in soil? 4.What form or forms of carbon are present in the soil run-off? 5.What carbon form change occurred? 6.WHAT’S THE BIG IDEA????? (copy and answer question 6 on p. 553) WHERE WOULD THIS STATION HAPPEN IN NATURE? 7.Show, on the diagram, where on earth this carbon transfer reaction might occur. Include arrows to show carbon’s movement. Label with station #.

Station 3 Carbonate rocks (such as limestone) contain carbon. What happens to these rocks when rain (which is weak carbonic acid ) falls on them ? (FOCUS QUESTION - discuss this with your lab mates before you begin) 1.Obtain two test tubes. Place 1 inch of acetic acid (CH 3 COOH) in one test tube and 1 inch of water in another test tube. 2.We will use Alka Seltzer to represent limestone(CaCO 3 ). Add a small piece of a tablet to each tube and compare what happens in each. Record your observations in words and pictures. 3.The reaction you are observing is shown below……. Please copy this into your lab notebook. Name the reactants and products. CaCO 3 +(CH 3 COOH)  Ca + CH 3 COO +H 2 O + CO 2 4. What do you think the gas bubbles are? In the real world, this reaction happens much, much slower and the resulting gas gradually dissolves rather than furiously bubbling off. Imagine how the reaction would change if the CO 2 dissolved into surrounding water rather than bubbling off into the atmosphere.

Station 3 Q’s 1.What form or forms did carbon take before and after this reaction? 2.What carbon form change occurred? 3.WHAT’S THE BIG IDEA????? (copy and answer question 7 on p. 554) WHERE WOULD THIS STATION HAPPEN IN NATURE? 4.Show, on the diagram, where on earth this chemical reaction might occur. Include arrows to show carbon’s movement. Label with station #.

Station 4  Limestone (CaCO 3 ) is a rock that contains a lot of carbon. Plate tectonic activity pushes these rocks deep inside the earth where it is very hot. What happens to the limestone as it is heated up? (FOCUS QUESTION- record and discuss this with your lab mates before you begin) 1.Measure the mass of the test tube. (be careful….test tubes can roll!) 2.Use the plastic weigh boat to mass out 1.5 grams of NaHCO 3 (this is used in place of the CaCO 3 ). Add mass of test tube and record this initial mass. 3.Put the NaHCO 3 in the test tube and heat for about 3 minutes. (wear goggles and always keep open end of tube pointed away from people’s faces!) 4.Observe any changes you see. Record your observations in words and pictures. 5.After heating, cover your test tube with a small piece of foil to prevent any water from being absorbed from the atmosphere. 6.Let the test tube cool for 1 minute. After 1 minute you can immerse it in water to speed cooling. 7.Make sure the test tube is dry, remove foil and weigh it again. Record.  Compare the before weight with the final weight. What accounts for the different in weight?

Station 4 Q’s 1.What form or forms did carbon take before and after this reaction? 2.What carbon form change occurred? 3. WHAT’S THE BIG IDEA????? (copy and answer question 7 on p. 556) WHERE WOULD THIS STATION HAPPEN IN NATURE? 4.Show, on the diagram, where on earth this carbon transfer might occur. Include arrows to show carbon’s movement. Label with station #.

Station 5  What do you think the seafloor looks like at a depth of 1-2 kilometers? In this station you will simulate how carbon changes forms in the ocean. How does carbon move from the shallow ocean to greater depths? (FOCUS QUESTION - discuss this with your lab mates before you begin) 1.Place 100 mL of water into one beaker. Add a small spoonful of baking soda (NaHCO 3 ) and stir until the solution is clear. 2.In a different beaker add 100 mL of water. Add 1 small spoonful of calcium chloride (CaCl 2 ) and stir until the solution is completely clear. 3.Add 8 drops of universal indicator to each beaker. Record your observations in words and pictures. 4.Pour the contents of the beakers together. Describe what you see. 1.What color? 2.What pH? (refer back to the Engage activity) 5.What evidence do you have that a solid has formed? You may have to wait several minutes for the solution to settle. You may even have to come back to this station later.  The solid is Calcium Carbonate. Look at your original two reactants from the separate beakers. Where did the calcium come from? Where did the carbonate come from?

Station 5 Q’s 1.What form or forms did carbon take before and after this reaction? 2.What carbon form change occurred? 3.WHAT’S THE BIG IDEA????? (copy and answer question 9 on p. 557) WHERE WOULD THIS STATION HAPPEN IN NATURE? 4.Show, on the diagram, where on earth this carbon transfer might occur. Include arrows to show carbon’s movement. Label with station #.

Station 6 What do you remember about PHOTOSYNTHESIS??? (FOCUS QUESTION - discuss this with your lab mates before you begin) Observe and sketch the plant. You’ll remember that plants need carbon to grow. Under the plant, neatly write out the balanced equation for photosynthesis. (you might want to look in your chemistry review notes!)

Station 6 Q’s 1.What form or forms does carbon take in the reactants and in the products of photosynthesis? 2.WHAT’S THE BIG IDEA????? (copy and answer question 4 on p. 558) 3.Where does photosynthesis happen in nature? List several places. 4.Show, on the diagram, where on earth this carbon transfer might occur. Include arrows that show carbon’s movement. Label with station #.

Station 7  What would you see if you dug into this compost pile? Where does all the carbon go that is in this decaying vegetation? (FOCUS QUESTION – discuss this with your lab mates before you begin) Decomposers need oxygen to break down organic matter. The chemical reaction for this type of aerobic decomposition is: C 6 H 12 O 6 + 6O 2 → 6CO 2 + 6H 2 O + energy In the absence of oxygen, other decomposers carry out anaerobic respiration. The chemical reaction for this process is: C 6 H 12 O 6 + → 3CH 4 + 3CO 2 + (less) energy  Please record both the above chemical equations for the two important decomposition reactions that happen on earth.

Station 7 Q’s 1.What form or forms did carbon take before and after these reactions? 2.What carbon form change occurred? 3.Why do people like Mrs. Nance encourage you to collect food scraps and yard waste? Why not just throw this “yucky” stuff away??? 4.WHAT’S THE BIG IDEA????? (copy and answer question 5 on p. 560) 5.Show, on the diagram, where this carbon transfer might occur. Include arrows. Label with station #.

Station 8 What do you remember about CELLULAR RESPIRATION?? (FOCUS QUESTION – discuss this with your lab mate before you begin) Neatly write out the balanced equation for cellular respiration. (you might want to look in your chemistry review notes!) Put 1 inch of water in the test tube. Add 5 drops of BTB and swirl gently to mix. Use a straw to blow GENTLY in to the solution. Record your observations. Rinse out the test tube and throw away the straw when you are finished. Clean up any mess you’ve made.

Station 8 Q’s 1.What form or forms did carbon take before and after this reaction? 2.What carbon form change occurred? 3.How do you know that CO 2 was produced? 4.WHAT’S THE BIG IDEA????? (copy and answer question 6 on p. 561) 5.Show, on the diagram, where on earth this carbon transfer might occur. Include arrows. Label with station #.

Reflect and Connect Q’s 1.Major Concept #2 refers to “several main reservoirs”. What are these carbon reservoirs on earth? 2. CO 2 dissolves into the ocean waters in both polar and equatorial regions. Would CO 2 dissolve more easily into cold polar water or warm equatorial water? Use specific data from lab to support your answer. 3.Is it bad to have CO 2 dissolving in the world’s oceans? Do a bit of research and record what you find out. 4.Many of our lab stations dealt with atmospheric CO 2. How does CO 2 enter the atmosphere? What does CO 2 do in the atmosphere? (you should research this too!) COMMENT