Purpose:
The purpose of this lab was that I prepared and used chemically reactive paper to measure the concentration of tropospheric ozone. The ozone test paper I used in this lab was first developed by Christian Friedrich Schoenbein (1799-1868), so it was called Schoenbein paper. At first, to prepare the Schoenbein paper, filter paper was coated with a mixture of potassium iodide, starch and water. To use the Schoenbein paper, I hanged it in my balcony, in air, out of direct sunlight, for 5-6 hours which will allow a chemical reaction to take place. If there is ozone in the air, Schoenbein paper takes advantage of its high reactivity. Ozone in the air will oxidize the potassium iodide on the Schoenbein paper to produce iodine. The iodine reacts with the starch to produce a purple color. The shade of purple on exposed Schoenbein paper correlates with the concentration of ozone present in the air at the test site. The two chemical are:
2KI + 03 + H2O → 2KOH + O2 + I2
I2 + starch → Blue or Purple color
Background Information and Bibliography:
Ozone is a normally happening gas that shields us from the sun’s UV beams. In the long run all that ozone encompassing earth means frame the Ozone layer situated inside the stratosphere. Having ozone in the stratosphere is ordinary however when it is found inside the limits of troposphere it can be destructive to any living being that possesses that territory. Tropospheric ozone happens when repercussions of human exercises alongside UV light, hydro carbons, and nitrate oxides join. Ozone can break down yields and woods and any living tissue. For plants, ozone can make plants close their stromata, which make water and carbon oxide diffuse inside any plants tissue. Because of this it additionally backs off photosynthesis which produces important oxygen to any biosphere. Ozone can likewise have genuine wellbeing consequences for people bringing on genuine lung issues. Basically ozone can weaken the capacity of lungs making it harder for any human to inhale particularly if any human is as of now determined to have any genuine lung imperfection.
Hypothesis:
According to Schoenbein color scale, the amount of ozone is close to 7.3. Even from such scientists from the American Lung Association, it can’t be lower the federal standards.
Materials:
Safety Goggles, Hot Plate, Cornstarch, Small Paint Brush or Popsicle Sticks, Paper Clip Hangers, Distilled Water, Printer Paper, Stirring Rod, 250-ml beaker, Filter Paper, PotassiumIodide, and Zip Lock Bags
Procedure:
Preparation Procedure for Testing Solution
1. Place 100 mL of distilled water in a 250-mL beaker. Stir in approximately 5 g of cornstarch.
2. Place the beaker on a hot plate. Heat the mixture, over low heat, while stirring, until it is thick and translucent.
3. Remove the beaker from the hot plate. Stir approximately 1 g of potassium iodide into the mixture.
4. Cool the solution.
5. Lay a piece of filter paper on a piece of printer paper and use a small paint brush or Popsicle stick to apply the paste evenly onto both sides of the filter paper. Apply the paste as uniformly as possible.(Note: For immediate testing, the paper is ready for use at this point.)
* Use soap to wash hands and scrub under fingernails after working with potassium iodide!!
If storing the Schoenbein paper for later use follow steps 6 nd 7 below.
6. Dry the Schoenbein paper in a drying oven, at a low temperature. Never expose Schoenbein paper to direct sunlight.
7. Place the strips (should be about 2cm wide) in an airtight ziplock bag and keep them out of direct sunlight.
Testing Procedure
1. If Schoenbein strips have been freshly made, they are ready for immediate testing. If strips have been stored, moisten a strip of test paper with distilled water and hang it, out of direct sunlight, at the test site. The strip must hang freely.
*Use soap to wash hands and scrub under fingernails after working with potassium iodide!!
2. Expose the strip for approximately 1-11/2 hours . Remove the strip and place it in an airtight ziplock bag out of direct sunlight until the results are recorded. If working with a partner one of your should choose and INDOOR location while the other should choose an OUTDOOR location out of direct sunlight.
3. Determine the ozone concentration of the air at the test site as follows:
a. Moisten the strip with distilled water, then compare the color of the strip with the Schoenbein Color Scale (see provided color scale) and determine the Schoenbein Number. If the color of the paper is not uniform, use the color in the area with the most conspicuous change to determine the Schoenbein Number.
b. Use internet weather sites or sling psychrometer to determine the relative humidity at the test site and round it to the nearest 10%. If you use the internet use a site that will allow you to get data by zip code (try www.weather.com or www.wunderground.com ).
c. Use to the Relative Humidity/Schoenbein Number Chart as follows:
i. Along the bottom of the chart, find the point that corresponds to the Schoenbein Number.
ii. Draw a line upward from the Schoenbein Number until it intersects the curve that represents the correct relative humidity.
Draw a line from the intersection to “ii” to the left side of the chart. Note your ozone concentration.
Data Collection and Observation:
September: 170
October: 168
November: 170
December: 165
January: 165
February: 168
March: 170
April: 175
Analysis:
During the hot weather, the Schoenbein color goes up, during the cold weather like snowy days , it goes down. I usually put the ozone at night and pick it up in the morning, during the warm weather, the Schonbein’s color is increased , and decreases during the cold snowy nights.
Abstract:
So our goal in this lab was to see if Schoenbeins paper could react color scale, our goal was to measure and see how the color changes, and during what climates it changes on mostly, as it already proved that during the hot weather the color scale hits to the higher point as which was pretty unexpected.’
Suggestions for Further Investigation:
For more color change and Schoenbeing’s colors depend on the climate, I would put more ozones during the warm weather because it is more interesting as the color numbers go up.
What Did You Personally Learn from the Experiment:
I learned that climate can actually react to the ozone, I did not know that during hot days color number goes up and goes down during the snow days.