Name: ______________________________________ Class M2 (0 ) Date: ____________ Partner(s):____________________________________ LAB - SIGNS OF CHEMICAL CHANGE? YEAST AND HYDROGEN PEROXIDE – when you combine hydrogen peroxide and yeast? Question: Does a chemical change occur Materials Yeast Thermometer Graduated cylinder Weighing dish Hydrogen peroxide Timer (20 mL) Funnel Flask Scale Procedure: Measure 20 mL hydrogen peroxide and pour in flask. Record temperature. Measure 1 g yeast and pour in flask. Gently stir. Record temperature every 10 seconds in data table. Carefully clean up equipment, rinse glassware and return everything to cart. Graph results. in the table below. Results: Record results Yeast and Hydrogen Peroxide Results TIME (sec) TEMPERATURE (C) Diagram: Make a drawing of the procedure and – “Before” “After”. Include clear labels. Graphing: On a sheet of graph paper, choose the best type of graph to use and graph the results. Make graph neat, precise and easy to read. Conclusion: Write a conclusion paragraph that contains the answers to these questions in complete sentences. You may write this by hand or on a computer and attach the paragraph to this lab sheet. Check off the boxes as you answer each question like this: and how it is different from a physical change. Define “chemical change” ☐ Explain that the goal of the lab is to observe whether there are any signs of ☐ chemical change so you can decide whether mixing hydrogen peroxide and yeast leads to a chemical change. Explain how you gathered your evidence. Did you use any of your senses? If so, ☐ which ones?
Name: ______________________________________ Class M2 (0 ) Date: ____________ Partner(s):____________________________________ LAB - SIGNS OF CHEMICAL CHANGE? – YEAST AND HYDROGEN PEROXIDE Question: Does a chemical change occur when you combine hydrogen peroxide and yeast? Materials Yeast Hydrogen peroxide Flask Thermometer Timer Graduated cylinder (20 mL) Scale Weighing dish Funnel Procedure: Measure 20 mL hydrogen peroxide and pour in flask. Record temperature. Measure 1 g yeast and pour in flask. Gently stir. Record temperature every 10 seconds in data table. Carefully clean up equipment, rinse glassware and return everything to cart. Graph results. Results: Record results in the table below. Yeast and Hydrogen Peroxide Results TIME (sec) TEMPERATURE (C) Diagram: Make a drawing of the procedure – “Before” and “After”. Include clear labels. Graphing: On a sheet of graph paper, choose the best type of graph to use and graph the results. Make graph neat, precise and easy to read. Conclusion: Write a conclusion paragraph that contains the answers to these questions in complete sentences. You may write this by hand or on a computer and attach the paragraph to this lab sheet. Check off the boxes as you answer each question like this: ☐ Define “chemical change” and how it is different from a physical change. ☐ Explain that the goal of the lab is to observe whether there are any signs of chemical change so you can decide whether mixing hydrogen peroxide and yeast leads to a chemical change. ☐ Explain how you gathered your evidence. Did you use any of your senses? If so, which ones?
3_lab_-_evidence_of_chemical_change_-_h2o2_and_yeast_-_students.docx