Breaking up is hard to do – Separating Sand & Salt

Purpose: The purpose of this experiment is to separate a mixture of sand and salt.

Materials: * Small beaker * Electric balance * Sand * Salt * Water * Graduated cylinder * Stirring rod * Filter paper * Flask * Rubber policeman * Wash bottle * Funnel * Bunsen burner complete with rubber tubing and a source of gas * Hot hands * Insulator pad * Ring stand complete with a ring * Wire gauze * Striker

Pre-lab Questions: 1. Water will be useful in separating the salt and sand because salt is soluble in water, which allows it to dissolve into a homogenous mixture, allowing for filtering of the sand. 2. Properties of sand and salt that will help separate them are that salt is water soluble, and the sand is insoluble in water. 3. The three things that could go wrong in this experiment are: * During the evaporation of water while using the Bunsen burner, the flask might crack or explode – this can be avoided by not heating the flask over a prolonged period of time, and not heating it too intensely. * Some of the sand may be lost during the filtration – this can be avoided by carefully filtering the mixture, and making sure that all of the sand has been washed off from the beaker, and the rubber policeman. * Some of the salt may be lost if the salt doesn’t dissolve completely or if some of the salt water is spilled – this can be avoided by making sure that all of the salt has dissolved, and by being very careful while stirring the mixture not to spill it.

Procedure: 1. Place a small beaker on the balance. Press the rezero button to make sure to take the mass of only the sand and salt sample and not the beaker. 2. Carefully pour the sand and salt mixture onto the beaker. Record the mass in your data table. 3. Measure out 10mL of water using the graduated cylinder. Add the water to the beaker and gently stir the sample with a stirring rod for several minutes. Be careful not to spill. 4. Obtain a piece of filter paper write your names near the top, on BOTH sides. Use the balance to mass the filter paper and record this mass in the data table. 5. Obtain a clean, dry flask and use the balance to determine its mass as well. Record the mass of the flask in the data table. 6. Prepare a filtering set-up as directed by your instructor. Slowly and carefully filter the mixture. First pour out as much water as possible, and then use a rubber policeman to scoop out the remaining sand. Make sure all the sand stays inside the filter paper. 7. Rinse off the rubber policeman and the beaker with as little water from the wash bottle as possible – TOO MUCH WATER WILL SLOW DOWN THE FILTERING PROCESS! 8. When filtering is complete, carefully remove the filter paper from the funnel and place on the indicated tray to dry overnight. 9. Set up your Bunsen burner and flask as directed by your instructor. Evaporate the water in the flask by boiling until the contents are dry. BE CAREFUL NOT TO HEAT TOO LONG OR TOO INTENSELY – CONTINUING TO HEAT A DRY FLASK WILL CAUSE IT TO CRACK OR EXPLODE! 10. When all the water has been evaporated, use the hot hands to place the hot flask on an insulator pad to cool. DO NOT PLACE HOT FLASK DIRECTLY ON THE COUNTER – IT WILL CRACK! 11. If time allows, use the balance to mass the cooled flask and its contents. If there is not enough time, leave a slip of paper with your names on it next to the cooling flask and the instructor will mass it for you. 12. The instructor will also mass the dried filter paper and sand. She will distribute this data in class on Friday, as well as on the class website. 13. BE SURE TO CLEAN UP BEFORE LEAVING!

Data Table:

Mass of dry sand and salt mixture (g) | 10.59 | Mass of dry, empty flask (g) | 129.87 | Mass of dry filter paper (with names already written) (g) | 1.02 | Mass of cool flask and contents (g) | 132.05 | Mass of dry sand and filter paper (g) | 9.53 |

Qualitative Observations: * Upon boiling the salt water, small pieces of salt were popping out of the flask * Not all grains of the sand were collected from the beaker

Calculations: 1. Mass of dry sand and filter paper – Mass of dry filter paper = Mass of sand
9.53g – 1.02g = 8.51g
The mass of sand is 8.51g. 2. Mass of cool flask and contents – Mass of dry, empty flask = Mass of salt
132.05g – 129.87g = 2.18g
The mass of salt is 2.18g. 3. Mass of sandMass of sand and salt mixture x 100% = Percent of sand
8.51g10.59g x 100% = 80.4%
The percent of sand is 80.4%. 4. Mass of saltMass of sand and salt mixture x 100% = Percent of salt
2.18g10.59g x 100% = 20.6%
The percent of salt is 20.6%.
Post-lab Questions: 1. According to my data the sum of the percent salt and sand equals 101%. The percentages do not equal 100% because there was an error in the experiment which resulted in an additional 0.1g of matter. 2. The separation techniques that were practiced in this lab were filtration and evaporation. * Filtration is effective in separating solids from liquids. During filtration a mixture is poured through a funnel fitted with filter paper. Filter paper has tiny holes allowing only liquid to pass through and solid particles to stay on the paper. * Evaporation is effective in separating particles in solutions. The solution is heated so that the solvent will evaporate, and the solid substance is left behind.
Conclusion:
The objective of the experiment was to separate a mixture of sand and salt. Through using given materials, and following the procedure, the objective was met. The mixture can be separated into sand and salt through filtration and evaporation. The sand can be separated from the mixture through filtration. In order to filter the sand from the mixture, salt must first be dissolved in water. The mixture of salt water and sand can be then filtered through a funnel fitted with filter paper. Filter paper only allows liquids though, allowing for the sand to stay inside it. The salt can be separated from water through evaporation. During evaporation the solvent evaporates, leaving solid particles behind. The overall results from the experiment are that the 10.59 grams of the heterogeneous mixture consisted of 8.51 grams of sand, and 2.18 grams of salt. The sand makes up 80.4% of the mixture, while salt makes up 20.6% of the mixture. What might have affected the results were errors. During the filtration process, not all grains of sand were collected. Also during the evaporation process, due to intensive heat salt started popping out of the flask. Even though matter was lost, the final mass of sand and salt is 0.1 grams heavier, than the original mass. This is also the reason why the percentages of salt and sand do not add up to 100%. The additional mass comes from an error in the separation processes. The water that was used to separate salt and sand could remain in the samples either from inadequate time period for the sand to dry, or evaporating. This could have been prevented through providing a longer amount of time for the sand to dry, as well as for the boiling of the solution. It would also be helpful to place the separated particles in hot oven for a period of time, to ensure that both samples are completely dry. In conclusion it is possible to separate various substances from one another through different techniques without changing the chemical makeup of the substance.