Procedure:
- Obtain 30g of cereal and grind the cereal to a powder with a mortar and pestle
- Transfer the cereal powder to a 400mL beaker and add 250mL of warm tap water
- Measure and record the mass of a magnetic stirring bar and add the stir bar to the cereal mixture.
- Place the beaker on a magnetic stirrer and stir the cereal water mixture for about 30 minutes.
- We discovered that mixing at a lower speed will cause more iron to attach to the magnet
- Wearing gloves, remove the stir bar from the beaker. Try to grasp the stir bar in the middle to avoid dislodging the iron from the stir bar.
- Here we observed a powdery gray substance, the iron, sticking in small clumps to the magnet.
- Dip the stir bar containing metallic iron in acetone
- We realized that washing it with water would be a little counterproductive, and so simply went to to the acetone which would dry it faster.
- Remove the stir bar from the acetone and allow it to dry.
- Measure and record the mass of the stir bar with the iron attached. Compare the amount of iron obtained with the information provided on the Nutrition Facts label of the cereal.
- We got .014g, or 14mg, from the lab test of the cereal. According to the box, one serving size (1 cup) of cereal contains 100% of the daily value for iron, which is 18mg. So considering the error that may have occurred in this lab, the difference is pretty reasonable, and it is safe to assume that at least if there isn’t 18mg of iron in every cup, it’s at least pretty close.
- Remove the iron filings from the stir bar by holding a stronger magnet under it with a weighing dish in between.
- Here, the iron is pulled down by the stronger magnet into the weighing dish, and after moving both the stir bar and the strong magnet the iron has been removed.
(results from allowing the iron to sit in hydrochloric acid all night were never observed)
Data Table:
Original Mass of Cereal: 30.0g
Mass of the Magnetic Stir Bar: 4.183g
Mass of the Observation Glass: 57.289g
Mass of the Observation Glass with the Magnetic Stir Bar and Iron: 61.486g
Mass of the Magnetic Stir Bar with Iron Attached: 4.197g
61.486 - 57.289 = 4.197
Mass of Iron Extracted from the cereal: 0.014g (14mg)
4.197 - 4.183 = 0.014
Percent of Iron in Cereal: 0.047%
Mass of the Magnetic Stir Bar: 4.183g
Mass of the Observation Glass: 57.289g
Mass of the Observation Glass with the Magnetic Stir Bar and Iron: 61.486g
Mass of the Magnetic Stir Bar with Iron Attached: 4.197g
61.486 - 57.289 = 4.197
Mass of Iron Extracted from the cereal: 0.014g (14mg)
4.197 - 4.183 = 0.014
Percent of Iron in Cereal: 0.047%
rESULTS:
At the end of the lab, only a small collection of iron had been separated from the cereal (0.014g). It was barely visible. This could be because the cereal did not mix with the magnet as long as it needed in order to collect the correct amount of iron. Also, some of the iron got pushed off of the magnet at some point during the process of transferring the irons into different containers. The daily value of Iron needed is 18mg, so what was recovered would not be accurate to that (the box says that in one cup of cereal, you get 100% of DV of Iron). If the cereal had been mixed longer, more iron may have been recovered.