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Adding Water Glass research here.
Water glass is a common name for sodium silicate, a chemical compound made from sodium oxide (\(Na_{2}O\)) and silica (silicon dioxide, \(SiO_{2}\)). The composition is more accurately represented as \((Na_{2}O)x\cdotp SiO_{2}\) or \(Na_{2}O\cdotp xSiO_{2}\), indicating a variable ratio of sodium oxide to silicon dioxide. The formula \(NaO\cdotp 3SiO_{2}\) mentioned in the query is a slightly incorrect representation of a particular ratio, typically written as \(Na_{2}O\cdotp 3SiO_{2}\). Key properties Composition: A colorless, crystalline solid or a clear, viscous liquid, often made by fusing sand and sodium carbonate (soda ash) at high temperatures.Solubility: Water glass is soluble in water, especially hot water, forming an alkaline solution. The solution becomes a hard, glass-like solid when it dries.Reactivity: In acidic solutions, the silicate ions react to form a hard, glassy silica gel. This property makes it useful as a bonding and sealing agent. Common uses Adhesive and cement: As a strong, high-temperature adhesive for paper, cardboard, ceramics, and more. It's also used in refractory cements for applications involving high heat.Concrete sealer and soil stabilizer: To reduce the porosity of concrete and masonry products, making them more durable and water-repellent. It is also used to stabilize soil during construction.Egg preservation: A traditional method for preserving fresh eggs by sealing the pores of the shell to prevent bacteria from entering.Detergents: Added as a builder in laundry and dish detergents, where its alkalinity helps in removing fats and oils.Engine repair: Used as a temporary fix for leaking head gaskets. The heat from the engine causes it to form a glass seal. The specific properties of water glass can be adjusted by altering the ratio of silica to sodium oxide, allowing it to be used for a wide range of industrial and consumer applications.
You can convert sodium bicarbonate (baking soda) into sodium carbonate (washing soda) by heating it in an oven or on a stovetop. This process, called thermal decomposition, drives off carbon dioxide and water from the sodium bicarbonate, leaving behind the more alkaline sodium carbonate. A common method is to bake it at around 200°C (400°F) for an hour, spreading it evenly on a baking sheet.
Steps to Convert Sodium Bicarbonate to Sodium Carbonate
Preheat the oven: Set your oven to a temperature of about 200°C (400°F).
Spread the baking soda: Pour a layer of sodium bicarbonate onto a baking sheet.
Bake: Place the baking sheet in the preheated oven for approximately 30 minutes to 1 hour.
Stir (optional but recommended): Stir the baking soda once or twice during baking to ensure all of it reacts evenly.
Observe the reaction: You will see the baking soda puff up and hear bubbling as water and carbon dioxide are released.
Check for completion: The conversion is complete when the bubbling and gas release stops, indicating all the sodium bicarbonate has been converted to sodium carbonate.
Cool and use: Let the baked baking soda cool, and it will now be sodium carbonate.
Chemical Reaction
The chemical reaction that occurs during this process is:
2 NaHCO₃(s) → Na₂CO₃(s) + H₂O(g) + CO₂(g)
To make molten sodium carbonate, you must heat the anhydrous salt to at least its melting point, which is 851 °C (1,564 °F). Heating it above this temperature will result in molten sodium carbonate, though it can decompose at very high temperatures, so temperatures around 900-1000 °C are often used for processes like molten salt oxidation.
Key points
Melting Point
: The precise temperature for sodium carbonate to become a liquid (molten) is 851 °C.
Anhydrous Form
: This melting point applies to anhydrous (without water) sodium carbonate.
Decomposition
: Sodium carbonate will decompose at sufficiently high temperatures, so it does not have a boiling point.
Practical Uses
: In practical applications, such as molten salt oxidation, temperatures of 900-1000 °C are used to ensure the salt is fully molten and to facilitate the process.
Sodium silicate is made by reacting silica (silicon dioxide), often from sand, with a sodium source, such as sodium carbonate (soda ash) or sodium hydroxide (lye), at high temperatures. The most common method involves fusing silica and soda ash in a furnace to form a glass-like mass, which is then dissolved in water to create "water glass," an aqueous solution of sodium silicate. Alternatively, silica can be dissolved in a hot, concentrated solution of sodium hydroxide under pressure in an autoclave to produce the desired solution.
Methods for Making Sodium Silicate
High-Temperature Fusion (Furnace Method)
Melting: Silicon dioxide (sand) and sodium carbonate (soda ash) are mixed and then heated to high temperatures, typically in a furnace.
Reaction: The silica melts and dissolves into the molten sodium carbonate, forming a glass-like solid.
Dissolving: This solid mass is then dissolved in water to create an aqueous solution of sodium silicate, known as water glass.
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