It is accepted ability that the freezing point of authentic baptize is at 0 degrees centigrade or 32 degrees ferinheight. However, is it accessible to accumulate baptize in its aqueous accompaniment beneath that freezing point? It is absolutely possible, and bodies accept been application this assumption for centuries! Traveling aback to the 1600s we acquisition King Charles I of England dining with his lords and ladies. The final advance is the gluttonous contentment of ice cream. It is ambiguous that King Charles I accepted the accurate assumption of black the freezing point of a solution; nevertheless, at that time it was absurd to accomplish ice chrism after freezing the crème by black the freezing point of baptize beneath 0 degrees centigrade (Zinger, 2005). Today, principalities advance alkali on icy anchorage in adjustment to “melt” the ice. In actuality, the alkali is alone black the freezing point of the water, acceptance the anchorage to abide ice chargeless alike while the temperatures are beneath 0 degrees centigrade.
To appreciate freezing point depression, you charge aboriginal accept freezing point. Simply put, it is advised the temperature at which a aqueous changes into its solid phase. However, it can additionally be anticipation of as the temperature at which the aqueous and solid phases are at calm with the atmospheric, or vapor, burden about it. Freezing occurs as baptize molecules become ordered into a apparent lattice.
Scientists accept continued accepted about the abnormality that back you add a solute to a solvent, the freezing point lowers, or depresses. Freezing point abasement is a colligative property. Colligative backdrop are the backdrop of solutions that depend on the cardinal of molecules in a solvent. It does not depend on the backdrop of the alone molecules in the band-aid (Prentice-Hall, 1972). As an example, back you actualize a band-aid by abacus sodium chloride as the solute, to the bread-and-butter of water, the freezing temperature of the band-aid decreases. The access of the cardinal of solute particles of the band-aid interferes with the development of the apparent structure, accordingly the freezing action is delayed (Newton, 1999). Freezing point abasement can be bidding mathematically as: ΔT = i Kf m. The ΔT equals change in temperature, i equals the cardinal of particles into which the solute dissociates, m equals the moles of the solute per kilogram of solvent, and Kf equals the molal absolution point connected (for water, Kf = 1.853 C/m) (thinkquest, 2010).
As discussed, solutes baffle with the alive of a aqueous to a solid state. The colligative backdrop chronicle to the cardinal of solute particles in a solution. The greater the solute particles there are in a solution, the greater the abatement in freezing temperature. If 10 grams of sodium chloride were added to 100 grams of water, the freezing point would bead to -5.9 degrees centigrade. However if 10 grams of sucrose were added to 100 grams of water, the baptize solution’s freezing point would alone bead to -0.56 degrees centigrade. Why the affecting aberration amid the two? After all, the aforementioned bulk of sucrose and sodium chloride was added to the aforementioned bulk of water. The acknowledgment lies in the cardinal of particles in anniversary solute. There are added particles in 10 grams of sodium chloride again there are in 10 grams of sucrose. Sucrose, C12 H22 O11, has a atomic weight of 342.3 grams per mole. Sodium Chloride on the alternative hand, has a atomic weight of 58.44 grams per mole. Sodium Chloride has about six times as abounding particles than sucrose has in the aforementioned cardinal of grams. Therefore, the sodium chloride band-aid has a lower freezing point than the sucrose band-aid (Chemistry Explained, 2010).
Not alone is it accessible to quantify the abasement of the freezing point of a solution, it is accessible to adumbrate how far the freezing point will be decreased. According to the attempt of the colligative properties, it doesn’t bulk what the concrete backdrop of the solute added to the band-aid may be. The alone free agency is the cardinal of particles in the solution. Therefore, if you bifold the bulk of sodium chloride in a solution, the abasement of the freezing point will be bifold the aboriginal solution.
The aboriginal catechism of, “is it accessible to accumulate baptize in its aqueous accompaniment beneath that freezing point?”, has best absolutely been answered with a aural yes. Not alone can it be lowered, that blurred can be understood, quantified and predicted. In the agreement appearance of this project, the accurate adjustment will be acclimated to appraise the authority of this research. King Charles I of England would be afraid to apperceive that his gluttonous contentment of ice chrism paved the way for the discoveries of colligative backdrop and blurred the freezing point of water.
A Brief History of Ice Cream, http://www.zingersicecream.com/history.htm
Colligative Properties, http://www.chemistryexplained.com/Ce-Co/Colligative-Properties.html
Solutions and Colligative Properties: Colligative Properties, http://library.thinkquest.org/C006669/data/Chem/colligative/colligative.html
W.J. Moore, Concrete Chemistry Prentice-Hall 1972
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