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1.Mixture is taken, and has to be measured in order to meet the requirements of 2-3g. 2.The mass of the tray is measured and then the scale is zeroed out and the mixture is added to find out the mass of the original mixture. 3.Next, find the mass of the 250mL beaker, zero out the scale, pour the mixture in, and weigh to find the mass. Find the mass of the 100mL beaker as well. 4.In order to separate the iron from the mixture, take a bar magnet inside of a Ziploc bag, and swirl it through the mixture. 5.The iron will stick to the magnet, and lift the magnet out of the mixture. All iron in the mixture should be on the magnet. 6.The iron taken out of the mixture is then measured to find the mass of the retrieved iron. 7.Next, the salt will be separated from the mixture. In order to do this, a ring stand must be set up with an iron ring and a glass funnel. Take a piece of filter paper and fold it as demonstrated by Mrs. Montoney, and place it in the funnel. 8.Place a 250mL beaker under the funnel for the filtered water. 9.Put the remaining mixture in the funnel.
10.Pour some water in a beaker, record the amount of water and pour it in the funnel. The mixture will begin to filter and drain the salt, leaving behind the sand. More water may need to be added depending on if the salt particles are fully desolved or not. 11.The sand has been recovered. Take the filter paper, unfold it, weigh its mass, and place it in the chemical oven to dry before measuring. 12.While the sand is in the chemical oven, take a hot plate, and place the beaker with the filtered salt water on the hot plate. The water will begin to boil, and eventually, the salt will be clearly visible and separated.
13.Once the salt is fully dried out, and no water remains in the beaker, remove the beaker with tongs for it will be extremely hot. Measure the beaker with the salt in it and subtract the original mass of the 250mL beaker to find the mass of the recovered salt. 14.The sand should be dry by now. Take the sand on the filter paper out of the chemical oven with extreme caution, place it on the scale, measure its mass, and then subtract the original mass of the filter paper in order to find the mass of the recovered sand. 15.The mixture is now separated into the three substances of sand, salt, and iron.
In order to complete this lab report, the following concepts must be understood. First, the difference between a mixture and a pure substance. A mixture is two or more pure substances combined, that keep their separate chemical identities and properties. The amounts of each pure substance in a mixture can change therefore the physical properties of a mixture depend on its composition, and the composition of a pure substance is constant giving pure substances characteristic physical properties that do not change. Physical properties that are used to describe pure substances include solubility, magnetism, and boiling point, which are all characteristics used in this lab.
The next concept is physical changes. Physical changes separate the components of a mixture, such as separating the iron, sand, and salt in this lab. Physical changes that can be used to separate mixtures include filtration, evaporation, and distillation. Mass percent composition is a way to express the real composition of a mixture by the amount of each component. In order to do this, the substances must be separated quantitatively. Lastly, percent yield which describes the efficiency of the “recovery operation” is calculated to separate the mixture. (Handout)
The observations for this lab are as follows:
•The original mixture is a brownish color, and the difference between the different substances can easily be determined by sight.
•When the water was poured into the mixture of sand and salt during the filteration process, the filtered water was coming through slowly in large drops.
•During the filtration process, the salt seemed to not be dissolving as quickly as thought, and more water was needed.
•When the salt water was being boiled, all of the sudden the water turned into what looked like foam and the salt started popping.
•When the sand was taken out of the chemical oven, salt particles that had not been dissolved were found on the bottom of the filter paper.
•The iron had a high magnetism, while sand and salt had none at all.
•The salt had a high solubility in water while the sand did not.
•The physical appearance of the iron resembled rough tiny little black hairs.