what is the freezing point of pure acetic acid being stirred and not being stirred. also at what point does it become a solid then a liquid, and vice versa.
I'm not sure what brought these questions on but the freezing point of anything is not a function of it being stirred or not.
When a solid is heated slowly (and best with stirring so the heating is uniform), the solid will begin to melt. At the point that both solid and liquid are present, the temperature reading is the melting point (freezing point). Adding heat will cause more solid to melt (but the temperature will not change) and cooling slightly will cause some of the liquid to solidify (but the temperature will not change). That is, the melting point (freezing point) is the temperature at which both solid and liquid are in equilibrium. When adding heat, the temperature will not increase until all of the solid has melted.
The freezing point of pure acetic acid, also known as glacial acetic acid, is dependent on whether it is being stirred or not.
When acetic acid is left unstirred, it forms crystals and freezes at approximately 16.6 degrees Celsius (62 degrees Fahrenheit). This is the point at which it transitions from a liquid to a solid state.
However, when acetic acid is continuously stirred or agitated, the formation of crystals is inhibited and it remains in its liquid state even below its normal freezing point. This phenomenon is known as supercooling. Supercooled acetic acid can exist as a liquid at temperatures below 16.6 degrees Celsius, until a disturbance occurs or a solid seed crystal is introduced.
When a supercooled acetic acid is disturbed or seeded, it rapidly solidifies, often accompanied by a sudden release of heat known as the "Mpemba effect". This effect indicates the rapid transition from a metastable state (supercooled liquid) to a stable state (solid).
To observe the freezing and melting points of acetic acid, you can perform the following experiment:
1. Take a sample of pure acetic acid in a container.
2. For unstirred freezing, cool the sample down to below 16.6 degrees Celsius. Crystals will start forming, indicating that the liquid is freezing.
3. For stirred freezing, continuously stir the sample while gradually decreasing the temperature. Despite being cooled below 16.6 degrees Celsius, the liquid will remain in a liquid state without freezing, under the supercooling effect.
4. To observe the transition from solid to liquid, heat the sample of frozen acetic acid. At approximately 16.6 degrees Celsius, the crystals will melt, and the solid acetic acid will turn back into a liquid.
It's important to note that the freezing point and phase changes of acetic acid may vary slightly depending on the purity of the sample and other factors.