Ammonium carbonate salt is prepared by the sublimation of a mixture of ammonium sulfate and calcium carbonate.
Understanding the Preparation Method
According to the provided reference, the primary method for preparing ammonium carbonate salt involves a specific high-temperature process.
The Sublimation Process
The key to preparing ammonium carbonate this way is sublimation. Sublimation is a process where a substance changes directly from a solid to a gas, without passing through a liquid phase.
The process involves heating a mixture of two specific starting materials:
- Ammonium Sulfate ($(NH_4)_2SO_4$)
- Calcium Carbonate ($CaCO_3$)
When this mixture is heated, the ammonium sulfate and calcium carbonate react, and the resulting ammonium carbonate goes directly into a gaseous state. This gas is then cooled, causing it to condense back into a solid form, bypassing the liquid phase.
Resulting Product
The ammonium carbonate obtained from this sublimation process occurs in specific forms:
- A white powder
- A hard, white or translucent mass
Practical Use: Leavening Agent
The reference also highlights a practical application of ammonium carbonate: it acts as a heat activated leavening agent. When heated (e.g., during baking), it breaks down into gases:
- Carbon dioxide ($CO_2$): Provides leavening (rise)
- Ammonia ($NH_3$): A gas that needs to dissipate
- Water ($H_2O$): Also turns into steam, contributing slightly to lift
This property makes it useful in certain baked goods, particularly those that are thin or low-moisture, allowing the ammonia gas to escape easily.
In summary, the preparation method detailed involves a solid-to-gas-to-solid transition (sublimation) using a specific mixture of starting materials.
