Question

Devise and describe an experiment to (a) Separate sucrose (table sugar) from water. (b) Separate the element sulfur from table salt (sodium chloride). (c) Separate iron filings from granular zinc.

Short answer

(a) Evaporate water to leave sucrose. (b) Use solvent and filter to separate sulfur. (c) Use a magnet to separate iron filings.

Step-by-step solution

Evaporation (Separating Sucrose from Water)

Begin by heating the sugar solution (sucrose dissolved in water) gently using an evaporation dish or a process. As the water heats, it will evaporate gradually, leaving behind the sucrose crystals. This process utilizes the difference in boiling points between water and sucrose, as water will convert to vapor well before sucrose begins to crystallize. Ensure that the heat applied is not too intense to prevent caramelization of the sugar.

Filtration (Separating Sulfur from Sodium Chloride)

Add a suitable solvent, such as carbon disulfide, to the mixture of sulfur and sodium chloride. Sulfur is soluble in carbon disulfide, while sodium chloride is not. Once mixed, the mixture can be filtered. The solution will contain dissolved sulfur, while the insoluble sodium chloride will remain on the filter paper. After filtration, evaporate the solvent to obtain pure sulfur.

Magnetic Separation (Separating Iron Filings from Granular Zinc)

Use a magnet to separate iron filings from granular zinc. Iron filings will be attracted to the magnet extraction tool because of their magnetic properties, while zinc will not be attracted. Move the magnet slowly over the mixture, ensuring that it isn't too close to risk cross-contamination, to segregate the magnetic component efficiently from the non-magnetic zinc.

Key concepts

Evaporation

Evaporation is a common and effective technique used for separation, especially when dealing with a mixture of a solid dissolved in a liquid. In our experiment, we aim to separate sucrose, or table sugar, from water. By heating the sugar solution gently, water will begin to evaporate. Water has a much lower boiling point compared to sucrose. This means it converts to vapor much sooner than sugar begins to crystallize.
This property allows us to separate the two effectively. As all the water evaporates, you're left with crystalline sucrose. It's important to apply heat carefully, though.

• Ensure the heat isn't too high to avoid caramelization.
• Use an evaporation dish for a steady heat application.

This method is simple and practical. It perfectly utilizes the different physical properties of substances—in this case, their boiling points.

Filtration

Filtration is a versatile technique used to separate solids from liquids and is particularly useful for heterogeneous mixtures. To illustrate this, we can separate sulfur from sodium chloride using filtration paired with a suitable solvent. The process begins by adding carbon disulfide to the mixture. Why? Because sulfur dissolves in this solvent, while sodium chloride does not.
By filtering the mixture, we can separate the solid sodium chloride from the sulfur solution. The solid residue (sodium chloride) remains on the filter paper, and the liquid portion (sulfur in carbon disulfide) passes through.

• After filtration, evaporate the solvent to crystallize sulfur.
• This carefully chosen solvent plays a key role in effective separation.

This technique highlights the clever use of solubility differences between substances to achieve separation.

Magnetic Separation

Magnetic separation is a straightforward and effective method for separating magnetic materials from non-magnetic ones in a mixture. In our setting, we need to separate iron filings from granular zinc. This method hinges on the magnetic properties of iron filings which are attracted to a magnet, whereas zinc is not.
By employing a magnet, you can efficiently extract the iron from the mixture. It's crucial to move the magnet slowly and carefully over the mixture to avoid accidental inclusion of zinc.

• Avoid placing the magnet too close to prevent cross-contamination.
• This technique utilizes the physical property of magnetism to achieve separation.

This process is not only efficient but also highlights the intriguing properties of materials and their interactions with magnetic fields.