Heating Substances Name: ______________________________ Period:_______ Date: _________________ When heated, many solids simply melt and become liquid. Do all solids undergo such a simple reaction when heated? Question: What is the effect of the type of a substance (sodium chloride, copper carbonate, copper sulfate, zinc oxide, sulfur) on the substance’s reaction when heated? (HINT: Which substance do you think will change/react the most?) Prediction(hypothesis):_____________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ Materials: 250 mL beaker Test tube holder 4 test tubes Small jars containing: sodium chloride (NaCl) copper sulfate (CuSO4) Lab scoop Alcohol burner Small test tube containing sulfur (S) copper carbonate (CuCO3) zinc oxide (ZnO) Procedure: 1. Place one lab scoop of the sodium chloride into a test tube. 2. Examine and record the physical characteristics of the substance. 3. Attach the test tube holder near the mouth of the test tube. 4. Ask your teacher to light your alcohol burner. 5. Heat the bottom of the test tube for 1-2 minutes as demonstrated by your teacher. Be sure to keep the test tube moving so that the substance is heated evenly and be sure to point the test tube AWAY from people. 6. Observe and record any changes that you observed. 7. Allow the test tube and the substance to cool for one minute. Place the test tube in the 250 mL beaker. 8. Repeat steps 1 through 7 for copper carbonate, copper sulfate, and zinc oxide. 9. Repeat steps 2 through 7 for sulfur. (the test tube of sulfur will be reused by the other classes) 10. When you finish heating all of the substances, extinguish the burner as demonstrated by your teacher. Karen Parrow (adapted from STC Properties of Matter) 2/12/2016 Page 1 Heating Substances 11. Observe and record the appearance of the substances after each substance has cooled down completely (after about 5 minutes). 12. Make sure that all of the test tubes are cool before disposing of the chemicals in the container labeled chemical disposal. Do NOT empty or clean the test tube containing the sulfur. 13. Use the test tube brush and water to clean the other test tubes thoroughly. Place the clean test tubes upside down in the test tube rack. 14. Compare your results to your classmates as a way of repeating the investigation. Type of Substance vs. Reaction When Heated Observations Type of Substance Appearance Before Heating Observations During Heating Appearance After Cooling Sodium Chloride (NaCl) Copper Carbonate (CuCO3) Copper Sulfate (CuSO4) Zinc Oxide (ZnO) Sulfur (S) 1 Which variable was a controlled (kept the same) variable in this investigation? o A. Kind of substance o B. Mass of substance o C. Density of substance o D. Amount of substance Karen Parrow (adapted from STC Properties of Matter) 2/12/2016 Page 2 Heating Substances 2 Which variable was the manipulated (changed) variable in this investigation? o A. Temperature of burner o B. Number of scoops used o C. Type of chemical substance o D. Changes that were observed 3 Which variable was the responding (dependent) variable in this investigation? o A. Mass of substance o B. Reaction when heated o C. Color of the substance o D. Appearance before heating 4 At the end of the investigation Jill learned that her prediction was not correct. What should she do? o A. Change her prediction to match the data o B. Change the data to match her prediction o C. Make no changes to the data or prediction o D. Select only the data that matches her prediction Karen Parrow (adapted from STC Properties of Matter) 2/12/2016 Page 3 Heating Substances 5 Write a conclusion for this investigation question. In your conclusion, be sure to: Answer the investigation question. Include supporting data from the Type of Substance vs. Reaction When Heated table. Explain how these data support your conclusion. Question: What is the effect of the type of a substance (sodium chloride, copper carbonate, copper sulfate, zinc oxide, sulfur) on substance’s reaction when heated? (in other words, which substance reacted the most? the least) Karen Parrow (adapted from STC Properties of Matter) 2/12/2016 Page 4 Heating Substances 6 Based on this investigation, which of the following phenomena is evidence of a chemical change caused by heating? o A. The substances solidifies o B. The substance melts o C. The mass changes o D. The color changes 7 8 What happened to the mass of the sulfur when the test tube of sulfur was heated and turned into a liquid? o A. The mass decreased because heat caused the sulfur to expand. o B. The mass stayed the same because no matter was created or destroyed. o C. The mass increased because the sulfur took up more room in the test tube. o D. The mass decreased because the heat burned up some of the sulfur molecules. When the blue-green powder, copper carbonate (CuCO3) was heated, the CuCO3 released carbon dioxide gas (CO2) and changed into a black powder (CuO). What happened to the mass of the substances when the blue-green copper carbonate was heated? o A. The mass of the black powder + carbon dioxide gas = the mass of the copper carbonate. o B. The mass of the black powder was the same as the mass of the blue-green powder. o C. The mass of the black powder was greater than the blue-green powder because the powder was burnt. o D. The mass of the blue-green powder was less than the black powder because the substance evaporated. Karen Parrow (adapted from STC Properties of Matter) 2/12/2016 Page 5 Heating Substances 9 What is air made out of? o A. Just oxygen molecules o B. Nothing; air is just space o C. A gas consisting of one kind of atom o D. Different kinds of atoms and molecules 10 Which of the following substances represents an element? o A. He o B. CO o C. H20 o D. NaCl 11 Carbon dioxide is made out of one carbon atom and 2 oxygen atoms. Which of the following correctly shows the arrangement of atoms in carbon dioxide? o A. COC o B. OCO o C. CCO o D. OCC 12 The density of copper carbonate is 3.9 g/cm³, but the density of copper sulfate is 3.6 g/cm³. Why is the density of the two substances different? o A. The substances are made out of different atoms. o B. Copper sulfate is heavier than copper carbonate. o C. Copper sulfate has more mass per cm³ than copper carbonate. o D. Copper carbonate reacts more when heated than copper sulfate. Karen Parrow (adapted from STC Properties of Matter) 2/12/2016 Page 6 Heating Substances 13 How is a solid such as sodium chloride different from a liquid such as water? o A. Solids are less dense than liquids. o B. Solids have more mass than liquids. o C. Solids have a specific volume; liquids can have any volume. o D. Solids have a definite shape; liquids take on the shape of their container. 14 Describe two different energy transfers that happened while using the alcohol burner to heat the substance in the test tube. In your description, be sure to: • Identify the energy forms before and after each energy transfer. • Describe when and where each energy transfer happened. Use words, labeled pictures, and/or labeled diagrams in your response. Draw and label a picture of the burner and the test tube over the flame. One transfer: Energy Input Energy Output System Another transfer: Type of Energy First System Receiving System Karen Parrow (adapted from STC Properties of Matter) 2/12/2016 Page 7 Heating Substances 15 Ammonium chloride and sodium chloride are both white crystalline solids, but ammonium chloride forms a white ring about half way up the test tube when heated. Use data and information from this investigation to describe a test that you could use to determine if an unlabeled jar of white crystals is ammonium chloride or sodium chloride. In your description be sure to: List the steps you would use Explain how you would know which substance was in the unlabeled jar Karen Parrow (adapted from STC Properties of Matter) 2/12/2016 Page 8