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Rate of Solution (9 Favorites)

LAB in Mixtures, Solubility, Reaction Rate, Saturated/Unsaturated/Supersaturated. Last updated October 8, 2019.


Summary

In this lab, students observe how particle size, solvent temperature, and agitation affect rate of solution.

Grade Level

High school

AP Chemistry Curriculum Framework

  • Big Idea 4: Rates of chemical reactions are determined by details of the molecular collisions.
    • 4.1 The student is able to design and/or interpret the results of an experiment regarding the factors (i.e., temperature, concentration, surface area) that may influence the rate of a reaction.

Objectives

By the end of this lesson, students will

  • understand factors that affect rate of solution.

Chemistry Topics

This lesson supports students’ understanding of

  • Kinetics
  • Solutions
  • Solubility

Time

Teacher Preparation: 30 minutes

Lesson: 45 minutes

Materials

  • Cup
  • Straw
  • Variable cards (see Teacher Notes)
  • Sharpie
  • Ruler
  • Balance
  • Granulated sugar
  • Sugar cubes
  • Superfine sugar
  • Water
  • Timer
  • Lemon juice
  • Ice cubes
  • Graduated cylinder

Safety

  • Food should never be consumed in a lab setting. Complete this activity in a nonlab setting.
  • When finding the mass of items that are intended for consumption, make sure they do not come into contact with the balance.

Teacher Notes

  • Create variable cards by writing on index cards the types of sugar, water temperature, and stirring frequencies. Have students select one card from each pile (three cards total) to assign what variables each group will investigate.

For the Student

Lesson

Prelab Questions

  1. What three factors affect the rate of solution?
  2. Predict which factor will have the biggest effect on the rate of solution.

Problem

In this lab, you will produce a sweet acidic solution (aka lemonade). You will look at how different factors affect the rate of solution of sugar.

Procedure

  1. Wash your hands. Pick up a plastic cup and a straw.
  2. Have each person in your group draw one set of variables. If two people have the same sets of variables, one of them should select a new card.
  3. Using a Sharpie, label your cup with your combination of variables. Using the ruler and a Sharpie, draw a horizontal line 2 cm from the top lip of the cup.
  4. Using a balance, measure 12 g of the appropriate sugar into your cup. If you have cube sugar and need a bit more to get 12 g, use a bit of granulated.
  5. Pour the appropriate temperature water to the line on your cup.
  6. Start the time for your table. If you are supposed to stir, stir with the straw. If you are supposed to leave yours still, you may stir once per minute for 3 seconds.
  7. Once the sugar is all dissolved, your group should note the time and record the data. Record the times for all of your group members experiments in your data table.
  8. Add about a tablespoon of lemon juice to your sugar solution. Stir. Add a couple of ice cubes if you want. Enjoy your lemonade.
  9. In a new cup, draw a line 2 cm from the top lip of the cup, like you did in step three. Fill the cup to the line with water. Using a graduated cylinder, measure how much water this is. Record that volume.

Data

Volume of water _____________________

Gather data from your classmates to complete the chart.

Sugar

Water Temperature

Agitation

Time to Dissolve

Cube

Cold

Stirred

Still

Room

Stirred

Still

Granulated

Cold

Stirred

Still

Room

Stirred

Still

Superfine

Cold

Stirred

Still

Room

Stirred

Still

Create a bar graph of the data.

Analysis

Write a one-page summary of what learned from this lab. Include the following:

  • Answers the prelab questions.
  • Explain the procedure in your own words.
  • What did you observe while doing this experiment? Does this fit with what you expected?
  • What factors that affect rate of solution did you include in this experiment? What factors did you not investigate?
  • Which factor seems to have the biggest impact on the rate of solution?
  • If you had investigated other factor(s), how do you think that would have changed your results?
  • Was the solution you made saturated, unsaturated, or supersaturated? How do you know?
  • Calculate the molarity of sugar in this solution. Sugar is C12H22O11.
  • How could this lab have been improved to give more accurate/reliable/scientifically sound results?