Lab report - The Effect of Iron on Human Body PDF

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The Effect of Iron on Human Body...

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The Effect of Iron on Human Body Introduction Iron is extremely useful in the human body in many different cases. There’s two types of iron, Iron (II) and Iron (III), prevalent in the human body. Iron (III) is used for dietary purposes in the body and there's two types of Iron (III), heme iron and non-heme iron (Ems and Huecker 2019). Heme iron is from the hemoglobin and myoglobin from animal sources, this is the iron we mainly use since we can absorb about 15-35% of the iron. For non-heme iron, this iron comes from plants and we don’t use this iron often since it is hard to absorb. For Iron (II) this is found in the hemoglobin to help transport oxygen throughout the body. When consumed iron travels to the stomach, which is met with hydrochloric acid, to allow the iron to be absorbed into the body (Jacobs 1971). Therefore, this experiment's purpose is to find the way iron reacts with different substances in everyday foods. Since sodium hydroxide (NaOH) has a pH of 14, I believe that if the substance pH is higher it will then take less amount of NaOH to reach the pH of 8. Methods and Materials First we obtained 50mL of 5% of sodium hydroxide (NaOH) solution and 30mL of pH 2 dissolved iron solution and placed both solutions in two separate beakers (Martyn). Then we placed 5 ml of pH 2 dissolved iron in a large test tube and slowly, using a dropper, dropped the 5% sodium hydroxide into the large test tube (Martyn). We would drop 3 drops at a time with a 5 second interval for each drop then 30 second intervals for when we do the next group of 3 drops (Martyn). We would then stir the solution in the large test tube using a glass stir then placed a small amount of the solution to a pH paper to determine the pH of the solution (Martyn). We would keep on doing this until the pH is 8 which would be a green color on the paper (Martyn). After we had the solution with the pH of 8, we would then discard the solution by placing it in the aqueous waste tub designated by our TA. We next measured out 0.2 grams of fructose, sodium

carbonate, and caffeine then placed each substance in their own test tube and placed 5 mL of pH 2 dissolved iron in each test tube and stirred the test tube until the solution dissolved (Martyn). After this we repeated the same steps as above by dropping the 5% of sodium hydroxide into the test tube and checking the pH of the solution until the solution turned to have a pH of 8 (Martyn). Results

Substance

pH before

Color/Texture Before

# of drops of NaOH

pH After

Observations after

NaOH

2

Clear Yellow Substance

31

8

Dark Red substance

Caffeine

2

Yellow, caffeine on bottom

17

8

Solid brown caffeine undissolved with a clear layer on top

Sodium Carbonate

6

Precipitate Orange, bubbly

5

8

Brown

Fructose

2

Yellow, clear, dissolved

25

8

Orangish Brown Cloudy

Oxalic Acid

2

Yellow Gold

36

8

Dark Orange, Cloudy

Tannic Acid

12

Black

0

14

Dark Black

Citric Acid

3

Crystalike white powder

60

8

Cloudy Dark Red

We first started with the control with just the pH 2 dissolved iron solution which was a clear yellow substance. When we added droplets of NaOH the substance then started to darken and turn red. It gradually turned into a higher pH with a total of 31 drops to turn the solution to have a pH of 8. We then did the 0.2g of fructose and the dissolved iron solution, which at first a yellow clear substance since the fructose instantly dissolved. This substance had a pH of 2 at

first then it took 25 drops of NaOH to turn the solution into one with a pH of 8. Which at the time was an orangish, brown cloudy solution. We then turned to the 0.2g of Sodium Carbonate with the dissolved iron solution, which had a pH of 6 when it first was mixed. This also formed an orange precipitate that was fizzing. We then had to place only 5 drops of NaOH for the solution to have a pH of 8, and the solution turned into a brown cloudy substance. Lastly we had the 0.2g of Caffeine and dissolved Iron solution. The caffeine did not mix with the dissolved iron solution but instead sank to the bottom and stayed there even after stirring the test tube. The solution remained yellow, then we added 17 drops of NaOH to the solution for the solution to obtain the pH of 8. The caffeine was still undissolved and at the bottom while a brown cloudy layer of solution was above the caffeine and another white clear layer was above the brown cloudy layer. Discussion/Data Analysis The method used to determine the volume of NaOH was multiplying the amount of NaOH dropped using the dropper and by our estimate of how much mL was in a single droplet. This method is not an accurate way of determining the amount of NaOH used since each droplet can contain a different amount in volume since the dropper is not precise enough. Also we used the pH paper to determine the pH but if we wanted more accurate results we would have used the pH meter. This is since a pH meter is more precise from the way the machine calculates the pH on its own to a certain number with a set number of significant figures, but for the pH paper it is not an accurate method for calculating the pH since it’s all about human estimation from determining the color of the pH paper and estimating the correct pH value to go with the color of paper. This shows how the pH paper method is more susceptible to human error. Furthermore human error could have played a big role in this experiment from either students not measuring out the correct 0.2 ±0.05 grams for each substance or instead not placing exactly 5mL of pH 2 dissolved iron. This could lead to skewed data if the amount is incorrect resulting in one side or the other. Another error that could have happened was placing

too many drops and it was too late for the pH to be 8. This had happened once to me, then I had restarted the fructose experiment to reach the pH of 8. To get more accurate data we should test the pH after every drop of NaOH instead of every 3 drops. According to Haylie Potter, most of the results are similar to mine (Potter 2018). We both stated how caffeine did not end up dissolving and still changed from a pH of 2 to a pH of 8, also we both found out that substances that have a pH of 2 or similar usually have the # of drops used around 20-30 drops (Potter 2018). Conclusion The data does not support my hypothesis since that if the substances had an inconsistent # of drops added to reach a pH of 8. For example, the solutions that started with a pH of 2 had a range of # of drops from 17-36 drops of NaOH. Then citric acid, which has a higher pH with 3, took in the highest amount of drops of NaOH with 60 drops. This shows that the data does not support the hypothesis

Works Cited

Ems, T.; Huecker, M. R. Biochemistry, Iron Absorption. In StatPearls; StatPearls Publishing: Treasure Island (FL), 2020. Jacobs A. Iron absorption. Journal of Clinical Pathology. 1971;s3-5(1):55–59. doi:10.1136/jcp.s3-5.1.55 Martyn T. Bioavailability of Iron. 1315-03 Bioavailability of Iron (1).pdf. 2018 Aug 13. Potter H. Bioavailability of Iron Lab report. Bioavailability of Iron Lab report. 2018....