ZERO-IN

Italicized font represents information to be shared orally or physically completed with the students at this time.

Non-italicized font represents additional information included supporting the teacher’s understanding of the content being introduced within the CELL.

ANALYZE IT

Instruct students to complete the Analysis Questions in their SDRs then discuss them as a class. Use the suggested responses below to guide students’ answers.

• Calculate: What was the rate of solubility for each compound when not stirred? Use the class data to complete Table H.

• Calculate: What was the rate of solubility for each compound when stirred? Use the class data to complete Table I.

• Did stirring increase the rate of solubility of each of the compounds? Use data from the experiment to support your answer. Stirring increased the rate of solubility of all of the compounds. When not stirred, none of the three compounds dissolved in less than 6 minutes. All of the compounds dissolved between 2 and 5 minutes when stirred.

• Why did stirring increase the rate of solubility of the compounds? Student answers will vary. Stirring increased the rate of solubility by dispersing the particles of solute more evenly so the particles of solvent could more easily surround the solute particles.

• Look at the data in Table I. Compare the chemical formulas of the compounds tested. Does stirring increase the solubility and rate of solubility of compounds made of similar elements? Stirring increased the rate and solubility of all the compounds composed of the same element. Stirring always increased the rate of solubility.

• Look at the data in Table I. Compare the chemical formulas of the compounds tested. Does stirring increase the solubility and rate of solubility of compounds made of different elements? Stirring increased the rate and solubility of all the compounds composed of the different elements. Stirring always increased the rate of solubility.

• Look at the data in Table I. Compare the chemical formulas of the compounds tested. Do the elements that make up the compound affect its rate of solubility? Each compound has a different formula and has a different rate of solubility suggesting that the differences in the chemical formulas affect the rate of solubility.

• Make a prediction. Are there any other ways to change the rate of solubility of a solute? Student answers will vary.

GET FOCUSED

Instruct students to complete the Focus Questions in their SDRs then discuss them as a class. Use the suggested responses below to guide students’ answers.

• What affects the solubility of a solute? Stirring increases the solubility of a solute. More of a solute can be dissolved in a solvent when the solution is stirred as compared to when it is not stirred.

• Can the rate of solubility of a solute be changed? Yes, the rate of solubility of a solute can be changed by stirring. Stirring increases the rate of solubility of a solute. A solute will take less time to dissolve in a solvent if stirred as compared to if the solution is not stirred.