Direction of shift Direction of shift Stress Stress (, , or (, , or no change) no change) Raise temperature Add Ag+NO3- Lower temperature Add Na+Cl- Equilibrium/Le Chatelier’s Principle Student Lab Sheet Activity 1: Iodine and Starch Materials: Starch solution Ice 1 (100 mL) graduated cylinder 2 (300 mL) beakers 3 (18 x 150 mm) test tubes Thermometer Tincture of iodine Hot plate/electric kettle Plastic pipettes Test tube rack Glass stirring rod Procedure: Measure 60 mL of starch solution using the graduated cylinder. Pour 20 mL of the starch solution into each of the three test tubes. Use the plastic pipette to add 1 drop of tincture of iodine to each test tube and stir with a glass stirring rod. Prepare an ice bath with ice cubes and water in a 300 mL beaker. Prepare a hot water bath by heating a 300 mL beaker filled with water on a hot plate until it reaches 800C; measure the temperature with a thermometer. Alternatively, obtain pre-heated water from your teacher. Place one test tube in the ice bath, one in the hot water bath, and leave one as a control. Observe and record the changes that occur. Data and Observations: Iodine (aq) + Starch (aq) Starch-Iodine Complex (aq) Stress Resulting color Control Raise temperature Lower temperature
Stress Direction of shift (, , or no change) Stress Direction of shift (, , or no change) Raise temperature Add Ag+NO3- Lower temperature Add Na+Cl- Equilibrium/Le Chatelier’s Principle Student Lab Sheet Activity 1: Iodine and Starch Materials: Starch solution 1 (100 mL) graduated cylinder 3 (18 x 150 mm) test tubes Tincture of iodine Plastic pipettes Glass stirring rod Ice 2 (300 mL) beakers Thermometer Hot plate/electric kettle Test tube rack Procedure: Measure 60 mL of starch solution using the graduated cylinder. Pour 20 mL of the starch solution into each of the three test tubes. Use the plastic pipette to add 1 drop of tincture of iodine to each test tube and stir with a glass stirring rod. Prepare an ice bath with ice cubes and water in a 300 mL beaker. Prepare a hot water bath by heating a 300 mL beaker filled with water on a hot plate until it reaches 800C; measure the temperature with a thermometer. Alternatively, obtain pre-heated water from your teacher. Place one test tube in the ice bath, one in the hot water bath, and leave one as a control. Observe and record the changes that occur. Data and Observations: Iodine (aq) + Starch (aq) Starch-Iodine Complex (aq) Stress Resulting color Control Raise temperature Lower temperature