BIO 135 WEEK 1 LAB REPORT TITLE: SEPARATION OF SALTWATER MIXTURE

BIO 135 WEEK 1 LAB REPORT TITLE: SEPARATION OF SALTWATER MIXTURE Title: SEPARATION OF SALTWATER MIXTURE Introduction: The purpose of this lab experiment is to separate a mixture of salt and water based on the physical properties of each substances by evaporation in order to determine the unknown percent of water to salt. Procedure: Percent Salt by Distillation (1) Obtain an electronic balance from the stock room by selecting the electronic scale from the equipment menu or from the popup context menu. (2) Obtain an 250ml beaker from the stock room by selecting the beakers from the equipment menu or from the popup context menu. (3) Weigh the clean dry 250 mL beaker and record its mass. To do this select the beaker and place it on the balance. Record the mass in the observation area. (4) Place 10 mL of the unknown salt water mixture to the beaker. To complete this task, remove the beaker from the scale and right click the beaker. Select the chemicals from the toolbar and select the unknown in the chemicals menu or the water menu item with the right-mouse-button context menu. Adjust the volume to 10 ml and select placed in picked. (5) Now weigh the unknown sample using the electronic balance. To weigh this sample simply place it again on the electronic balance and record to the .001grams. Remove the beaker from the balance. (6) You are now going to separate the salt water mixture by evaporating the water. To complete this task select the Bunsen burner from the tool bar and place it directly under the beaker’s new position. Next, right click the beaker and select the thermometer option. .As the water begins to boil record the temperature of the water. Allow the water boil off. You will see only a black mass, with exactly two bouncing spheres when the water is completely gone. Once the water is gone remove the flame from the beaker and allow it to cool to 20degree’s Celsius’s. and reweigh the beaker. This will be the weight of the salt. Record its mass. (7) You will calculate the percent mass of the salt based on both the salt and water lost. Observations and Results: 1. Mass beaker _____75.00_______ g 2. Mass beaker + Mixture _____85.175_______ g 3. Mass beaker + Salt _____75.175_______ g 4. Mass of Salt(3-1) ____0.175________ g 5. Mass of water(3-2) _____10.0_______ g 6. Temperature at which water began to Boil _____100_____C CALCULATIONS Method 1: Calculate percent by mass of salt in the mixture based on the mass of salt recovered. ( #4 / #5) X 100 (0.175/10)100 = 1.75% Discussion: I was able to obtain dry salt as a residue due to the heating of the water in this lab. Since a mixture is a physical combination of materials, the components could be separated using physical changes. Because the water has a significantly lower boiling point than the salt, the process of evaporation allows the water to boil away leaving only the dry salt. Conclusion: The process of evaporation in this lab experiment is able to prove that a mixture composed of various substances and components can be separated by physical means, changing phases. Therefore, the results from this method yield 0.175g of salt and 10.0g of water from the separation of mixture in the beaker. Therefore, the percent by mass of salt in the mixture based on the mass of salt recovered is 1.75 percent.