<p> Evidence for Chemical Reactions</p><p>Problem:</p><p>What evidence shows that a chemical reaction has occurred?</p><p>Materials:</p><p>3 test tubes test tube rack iron nail white vinegar calcium carbonate barium chloride solution potassium sulfate solution lead (II) nitrate solution potassium iodide solution copper (II) sulfate solution</p><p>Procedure:</p><p>1. On your table you will find the following chemicals: Barium chloride Iron nail Potassium sulfate, Calcium carbonate chip Lead (II) nitrate Copper (II) sulfate Potassium iodide Vinegar</p><p>2. In the chart provided, write the formula of each substance under its name</p><p>3. Observe the appearance of each solution and record your observations in your data table.</p><p>4. Using the droppers provided, add a dropper-full of potassium sulfate to a clean test tube. Add barium chloride solution drop by drop and make your observations and record them in your data table.</p><p>5. Add a dropper-full of potassium iodide solution to a new test tube. Add lead nitrate solution drop by drop. Make observations and record in your data table. 7. Add a dropper-full of copper sulfate solution to a clean test tube. Place the iron nail into the test tube. Observe what happens over the next 10 mins. Record your observations in your data table.</p><p>8. Add a dropper-full of vinegar to a clean test tube. Add the calcium carbonate chip to the test tube. Make your observations and record in the data table.</p><p>Observations: Table 1</p><p>Substances and their formulas Observations</p><p>Barium chloride</p><p>Potassium sulfate</p><p>Lead (II) nitrate</p><p>Potassium iodide</p><p>Copper (II) sulfate</p><p>Vinegar (Acetic acid)</p><p>Iron nail</p><p>Calcium carbonate chip Table II Reactants Observations</p><p>Potassium sulfate + Barium chloride</p><p>Potassium iodide + Lead nitrate</p><p>Iron + Copper (II) sulfate (Note: Iron will form Iron (III) ions)</p><p>Calcium carbonate + Acetic acid (Note: acetic acid is HC2H3O2) Analysis</p><p>1. Each of the changes you observed involved a chemical change. What evidence showed that a chemical reaction took place when you combined the barium chloride solution with the potassium sulfate solution?</p><p>2. What evidence showed that a chemical reaction occurred when you combined the lead nitrate solution and potassium iodide solution?</p><p>3. What evidence showed that a reaction occurred when you placed the iron nail into the copper sulfate solution?</p><p>4. What evidence showed that a reaction occurred when you added the calcium carbonate to the acetic acid solution?</p><p>Conclusion</p><p>1. Write a paragraph about the kinds of changes that you would expect to see whenever a chemical reaction occurs </p><p>2. Any one of these signs is not always a foolproof indication that a chemical reaction is occurring. Give two examples to support this statement.</p><p>3. Write the balanced chemical equation for each of the reactions that took place during this lab.</p><p>4. Name the type of reaction for each of the reactions that took place during this lab.</p>