Iodine Clock Design a Lab

Iodine Clock Design a Lab

Iodine Clock Design a lab (ver. 2016)

Planning will be Thur and Friday 5/5& 6/16; chemicals for the lab will available on Tuesday 5/10/16; reports will be due the following Monday 5/16/16

You may work with up to 3 other people (4 maximum per group; you must have a lab partner you can not work alone). You must design a series of experiments where you manipulate one (and only one variable) to change the rate of the reaction that you see demonstrated. (A + B  wait for it…. Ta Dah!).

Things that you may consider manipulating include: Concentration of “A”, concentration of “B”, Temperature of “A”,”B”, or both, use of a catalyst, etc.

Each group will be limited to 100 ml of each reactant so plan accordingly.

You will only be given one day to conduct your experiments so make sure your plan is detailed and easy to understand. Analysis of the experiment must include a properly produced graph of the data you collect.

I will provide a blank form that you can use as a general outline for planning, conducting and reporting your experiment.

Materials I plan on having available include:

Test tubes (small ones with rack available)

Thermometers

Clock on the wall (stop watches available upon request)

Warm and cold water (ideal for “baths” to gently warm or cool your reactants)

Small plastic beakers (remember: You are responsible for the sterility of all equipment)

Hot water available from various heating pots, ice in the Styrofoam cooler

(The product of this one way reaction can be disposed of down the drain)

Any other equipment must be provided by you or secured by special request (not on demand)

At each station you will find: (stations must be left clean and intact)

2 small plastic beakers labeled “A” and “B” to get your groups chemical supplies

(I would make sure they are clean; the teacher doesn’t do dishes)

2-small glass graduated cylinders (10 ml)

1-larger plastic graduated cylinder (100 ml)

1 larger glass beaker with an insert rack (perhaps to use as a warm/cold water bath)

1 smaller plastic beaker (50ml) (perhaps mixing or reaction container)

1 larger plastic beaker (400ml) (perhaps mixing or reaction container)

10 test tubes in a small rack

1 Thermometer (report all temperatures in o Celsius)

Generic Experimental Procedure write-up Format

EXAMPLE

Names:_(Do not use this “Form”; this is a format)_Date: ___ period: ___

Title: ___Manipulating a rate of reaction__(reports do not have to be typed , BUT they must be neat)____

a) Introduction:

Background information:

Question / Purpose:

Identify the major variables: (not all labs really fit this forma, but you can usually use this reasoning)

Dependant (responding variable) ___TIME TO COLOR CHANGE_____

Independent (manipulated variable) ______

Key control variables (what you kept the same) ______

Hypothesis: ____We Think that if we …______

b) Design and conducting the Investigation:

Materials List:

______

______

______Diagram of setup

Procedure: ______

______

c) Lab work Data collection and data table (include units, and error)

d) Analysis of data (a graph and/or calculations)

e) Conclusion:

f) pegwueurwetyueieyrueyryuelllenptriaselleisnsoncol

g) Further research or investigations

The reactants are:

Solution A: starch, a little sulfuric acid and 0.4 grams of NaHSO3 per liter

(which is .4 g (1 mol / 104 g) = 0.0038 molar NaHSO3)

Solution B: 2.0 grams KIO3 per liter

(which is 2.0 g ( 1 mol / 214 g ) = 0.0093 molar KIO3)

Students were given this information if they wanted it and it seems some did a little on-line research as well

Example Lab Report Format for Iodine Clock Reaction

a) Hypothesis:

  1. Generate a hypothesis based on an observation or data, use the hypothesis to make a prediction and support with reasoning (a “because…” statement)
  2. Ideas for wording:
  3. I hypothesize that… because…
  4. Based on…, I think that…
  5. If we add… then I expect… to happen, because…
  6. Example: I believe that reaction rate will increase if I decrease physical size, affecting the physical state, of my reactants because the increased surface area of reactants will let molecules interact more quickly.

b) Procedure:

  1. Describe all the materials and chemicals that will be used, step by step as you perform your experiment. These can be numbered steps, bulleted points, or paragraphs, including a picture or diagram is a great idea for extra clarity. The procedure should be clear enough that a classmate could carry out your experiment without extra details.
  2. Ideas for wording:
  3. For comparison, we need a control…
  4. Using… measure…
  5. As the reaction progresses…
  6. Repeat steps… for all remaining trials.
  7. Example:
  8. Using a graduated cylinder, measure out 10mL of each reactant and put in 50mL beakers labeled A and B.
  9. Simultaneously pour reactant A and B into a 100mL beaker, start the stopwatch. (3, 4, etc.)

c) Data:

  1. The data can be collected in any format that works for you. Since you are required to include a graph with 5 data points, a table is commonly chosen. Remember that you can include qualitative observations along with quantitative data (consider making an observations column).
  2. Ideas for observation wording:
  3. I notice that…
  4. I observed that…

d) Conclusion:

  1. See the rubric for the five questions that are required to be included in the conclusion
  2. Example wording:
  3. The data show that…
  4. I think one reason for… was…
  5. There is a linear relationship between…
  6. … combines with… to produce…
  7. Based on these numbers (or the graph), it is likely that…
  8. Our research has demonstrated that…
  9. The control group didn’t get treatment.
  10. As the… increases, the… decreases
  11. There is a correlation between… and…
  12. Several factors contributed to the…
  13. We discovered that…
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