Skip to main content

What is the effect of impurities on freezing point?

The freezing point of a liquid is the temperature at which the solid and liquid forms of the substance are in equilibrium (co-exist). When water is cooled, at 0 degrees Celsius, water starts freezing. On further cooling, the temperature will remain unchanged until the freezing is complete. This temperature (0 C) at which ice and water co-exist is called the freezing point of water. 


When a non-volatile solute is dissolved in a liquid, the vapor...

The freezing point of a liquid is the temperature at which the solid and liquid forms of the substance are in equilibrium (co-exist). When water is cooled, at 0 degrees Celsius, water starts freezing. On further cooling, the temperature will remain unchanged until the freezing is complete. This temperature (0 C) at which ice and water co-exist is called the freezing point of water. 


When a non-volatile solute is dissolved in a liquid, the vapor pressure of the solvent is lowered. The vapor pressure of the solution thus formed will be always less than that of the pure solvent. This phenomenon is called lowering of vapor pressure. Lowering of vapor pressure is a colligative property. A colligative property depends on the number of solute particles in the solution, and is independent of the nature of the solute. The magnitude of a colligative property is proportional to the mole-fraction(concentration) of the solute in the solution.  


When a dilute aqueous solution of NaCl is cooled, at a particular temperature ice starts forming. This temperature is called the freezing point of the solution. The freezing point of the solution will always be below that of the pure solvent. This is a consequence of the lowering of the vapor pressure. This phenomenon is called freezing point depression, which also is a colligative property.


Thus, an aqueous NaCl solution will freeze at a temperature below 0 degrees C, which is the normal freezing point of water. In general, a solution with a solute (regarded as an impurity in the study of colligative properties of dilute solutions) has a freezing point below that of the pure solvent.


Measurements of colligative properties can be used to determine the molar mass of the solute.                                     

Popular posts from this blog

In chapter one of The Great Gatsby, what advice does Nick's father give him? How does this make him a good person to tell this story?

Nick says that his father advised him that, before "criticizing anyone," he "remember that all the people in this world haven't had the same advantages" as Nick.  As a result, Nick claims that he is "inclined to reserve all judgments," presenting himself to the reader as a fair and dispassionate arbiter of character, and thus, a reliable narrator.   The problem is that Nick immediately reveals himself as anything but reliable, as he then launches... Nick says that his father advised him that, before "criticizing anyone," he "remember that all the people in this world haven't had the same advantages" as Nick.  As a result, Nick claims that he is "inclined to reserve all judgments," presenting himself to the reader as a fair and dispassionate arbiter of character, and thus, a reliable narrator.   The problem is that Nick immediately reveals himself as anything but reliable, as he then launches into a discussion of how pe...
Post a Comment
Read more

How and why does James Gatz become Jay Gatsby? Describe the young Gatsby/Gatz.

James Gatz, a poor Midwestern boy of probable Jewish lineage, becomes Jay Gatsby, a presumed WASP and wealthy socialite, when he moves to New York City and acquires his fortune. It is wealth that has allowed Gatz to transform himself into Gatsby. However, those who know his background (e.g., Daisy and Tom Buchanan) never allow him to forget that he is nouveau riche -- that is, an upstart who has just recently made his fortune,... James Gatz, a poor Midwestern boy of probable Jewish lineage, becomes Jay Gatsby, a presumed WASP and wealthy socialite, when he moves to New York City and acquires his fortune. It is wealth that has allowed Gatz to transform himself into Gatsby. However, those who know his background (e.g., Daisy and Tom Buchanan) never allow him to forget that he is nouveau riche -- that is, an upstart who has just recently made his fortune, whereas they arose from well-to-do families. Gatz became Gatsby through determination and discipline. At the end of the novel, the narr...
Post a Comment
Read more

Explain and discuss how the definitions of freedom change for the nation, for the freedmen and for southern whites after the Civil War.

After the Civil War, the definition of freedom changed in the nation, as slavery was ended with the 13th Amendment to the Constitution in 1865. The practice of slavery was disallowed, but definition of the freedom that would take its place was a subject of controversy, ongoing debate, and even violence in the decades to come.  For freedmen, freedom often meant reconciling with their families, who were broken up by slavery; choosing which church to... After the Civil War, the definition of freedom changed in the nation, as slavery was ended with the 13th Amendment to the Constitution in 1865. The practice of slavery was disallowed, but definition of the freedom that would take its place was a subject of controversy, ongoing debate, and even violence in the decades to come.  For freedmen, freedom often meant reconciling with their families, who were broken up by slavery; choosing which church to belong to without being ordered to attend religious services (or not to attend) by their mast...
Post a Comment
Read more