Mixture Lab Write Up
Introduction Purpose:
The purpose of the experiment was to use various lab equipment and lab techniques to separate a mixture of salt, sand, and water. Background: An element is the simplest form of a substance that retains the properties of that substance. A compound is a substance formed by combining two or more elements set in fixed proportions. A mixture is a system of two or more distinct chemical substances. Unlike compounds, mixtures can be physically combined. Because the components are physically combined, they can also be separated using physical properties. Physical properties are properties that do not change the chemical nature of matter. In this lab, a mixture of salt and sand will be separated using the listed equipment and separation techniques. Hypothesis: If a mixture of sand (3. 3g), salt (1. 2g), and water are separated using filtration and boiling point, then most of the sand and salt will be recovered. Safety Information: During the experiment, appropriate safety wear should be worn at all times such as goggles and an apron (to prevent salt or hot water from entering the eye).
Beaker tongs should be used to remove the heater beaker from the appropriate heating fixture and then it should be carefully transported onto the designated pressed fiber pad to cool.
Materials and Methods:
- Graduated cylinder
- Small beaker (100 mL)
- Large beaker (600 mL)
- Hot plate
- Small ring
- Funnel
- Filter paper
- Glass stir rod with a rubber policeman
- Hot mitts
- Beaker tongs
- Pressed fiber pad
- Weigh boat
- Electronic balance
- Scoops
- Salt and sand sample
- Water
Experimental Procedure
- Put on appropriate safety wear
- Begin this experiment with 47 mL of water, 1. 2 g of salt, and 3. g of sand.
- Use the 100 graduated cylinders to find the 47 mL of water, reading from the meniscus.
- Put the weigh boat onto the electronic balance and zero it out, then slowly add the salt until you have 1. 2 grams of it. Do the same for the sand.
- Also, mass the larger of the two beakers
- Combine the 1. 2g of salt and 47 mL of water into the 100 mL beaker and stir until the salt is dissolved
- Add the sand and wait until it settles onto the bottom of the beaker.
- Mass the filter paper and then fold it into a small cone. Wet sides before placing them into a funnel that is inside a ring stand. Place larger beaker underneath funnel.
- Slowly pour sand and salt mixture through filter paper. Let the sand dry.
- Take a large beaker with salt and water and place it on top of a hot plate. Set a hot plate onto its highest setting and let boil.
- Once salt starts popping lower temperature on a hot plate. When most of the water has evaporated remove from the hot plate using beaker tongs and let rest on pressed fiber pad.
- urn hot plate off.
- Mass out recovered sand and salt.
Results Raw Data:
| Object | Mass (g) |
| Starting mass of salt | 1. 2g |
| Starting mass of sand | 3. 3g |
| Dry filter paper | 0. 7g |
| Larger of the 2 beakers | 103. 1g |
| The total mass of beaker/salt (after) | 105. 3g |
| Mass of recovered salt | 2. 2g |
| The total mass of filter paper/sand (after) | 4. 1g |
| Mass of recovered sand | 3. 4g |
Important results:
- The mass of recovered salt was 2. 2g
- The mass of recovered sand was 3. 4g
- The percent error for the mass of recovered salt was 83% error
- The percent error for the mass of the recovered sand was 3%
- The percent yield for the mass of the recovered salt was 183% * The percent yield for the mass of the recovered sand was 103%
Calculations:
Discussion Expected results v.
Actual results: In the experiment, the mass of the salt recovered was larger than the mass of the amount of salt that was started out with. This may be due to the tap water that was used not being pure or that some sand was small enough to not be filtered out.
Analyze experimental error: During the experiment, instead of measuring the water out to exactly 47mL, around 60 mL of water was used. This could have caused there to be extra water during the final measurement. There was not enough time to boil off the extra water; this was done by another person later without either partner in the group supervising. Also, when looking for the sand sample the next day, it was missing; so another group’s sand data was massed instead.
Improvements: Having a longer time to conduct the experiment might have changed the data. Instead of leaving the sand sample in the open on a table to all classes, it may have been better for them to be separated more.
Results in terms of the purpose: The goal was to get most of the salt and sand back through filtration and evaporation. Most of the sand was recovered; however, there was a great deal of added mass to the salt (around 1g). The goal was met as far as data is concerned.
Conclusion: The goal of the experiment was to see if using boing point and filtration could recover close to the same amount of salt and sand put together in a mixture. The experiment revealed a percent yield of 183% for salt and 103% for sand, which does support the hypothesis that using those two techniques, about the same amount of salt and sand would be recovered.
