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What Are Effects Of Impurities On Melting Point?

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Connor Sephton Profile
Connor Sephton answered
The presence of an impurity in a pure substance will affect the boiling point of the substance, as it will increase the boiling point. This is quite simple to explain, and also quite easy to understand. However, the following explanation includes the example of water (the pure substance) mixed with salt (the impurity) to make a solution, in order to make the explanation even more clear.

If an impurity is present in a pure substance, the boiling point of the substance will be increased. Take the example of water. Pure water should boil at 100˚ Celsius. However, if you add granules of salt to water before boiling it, the presence of the salt may result in raising the boiling point of this solution by as much as one or two degrees Celsius.

The reason why the boiling point of the substance is raised is because the two components in the solution - in this case, the water and the salt - form chemical bonds with each other. These bonds require a lot of energy in order to break them. In this case, the bonds are being broken by heat energy, when the solution is heated to temperatures of over 100˚ Celsius. However, it requires more heat energy to break the bonds in order to boil the water, than it takes to simply boil pure water on its own. As more heat energy is required, the boiling point of the solution increases.

It may help you to think of the impurity - in this case, the salt - as a magnet or glue, holding the solution in its liquid form. In order for the liquid to change into its gaseous form when it reaches its boiling point, the liquid needs to break contact with the magnet or the glue, and this requires more heat energy.
Anonymous Profile
Anonymous answered
Impurities lowers the melting point of substances an increases the boiling point , causing them to have a wider range of temperature for melting and boiling.that is the more the amount of impurities in a substances the lower it melting point.
d ds Profile
d ds answered
A substance boils when the vapor pressure of the liquid will equate the pressure from the outside. As more and more liquid comes into contact with the atmosphere, more and more vapors will be released exerting a higher vapor pressure. If we add impurities to the liquid then these impurities block the way of the molecules which means lesser will escape as steam which decreases the vapor pressure and more energy that is supplied from heat is needed to boil the liquid. This means that boiling point goes up. Impurities lower the melting point of the substance if they are soluble in the substance because a lower temperature is needed to break the bonds between liquid and impurity molecules because the freezing point is related to the structure that is disturbed by the impurity.
Anonymous Profile
Anonymous answered
Impurities lower the melting point by disrupting the crystal lattice formed by a pure compound. Higher melting points are associated with more tightly packed crystal lattices
Aisha Profile
Aisha answered
The impurities play a major role against the boling or melting point of liquids. They interact with the molecules and make their melting points higher than the average.
Tauseef Sheikh Profile
Tauseef Sheikh answered
Impurities lower the melting point. The freezing point of a solution (which contains the impurity) is lower as compared to that of the pure substance.
Anonymous Profile
Anonymous answered
Boiling is used to describe a change of state of a pure liquid to vapour phase. The particular temperature at which this change of state occurs is defined as the boiling point of that specific liquid.
Now the question is will addition of impurities have any effect on the boiling point of water. The addition of impurities such as salt or sugar to pure water raises its boiling point. The antifreeze added to the water I
Anonymous Profile
Anonymous answered
If you add an impurity to the water ie: Salt the water may have to boil at a higher temperature in order to dissolve the impurity completely
Anonymous Profile
Anonymous answered
Any impurity in a sample will lower the melting point, even if the impurity melts at a higher temperature. An impurity will cause the sample to melt over a wider range.
Anonymous Profile
Anonymous answered
How about if the impurity's boiling point is lower than the substance? It will not effect the boiling point of the substance!
Anonymous Profile
Anonymous answered
When impurities is put into a liquid for example water, the temperature would decrease and so for it to boil, it would take a longer time.Therefore, changing the boiling point to a higher temperature."(depending on the other factors that can also change the boiling point)
Kody Goodwin Profile
Kody Goodwin answered
A solute will raise the freezing point and lower the boiling point.  This would also be the correct vocabulary to use, not melting point.
Anonymous Profile
Anonymous answered
Increases Boiling Point.

Solutes dissolved in solvents.
=>Freezing Point depression and Boiling Point Elevation.
Anonymous Profile
Anonymous answered
Impurities lower the melting point and increase the boiling point of pure substances, causing them to have a wider range of temperature for melting/ boiling. The more the amount of impurities, the lower the melting point and the higher the boiling point.
Anonymous Profile
Anonymous answered
The boiling point of that pure substance increaces and the melting point of it decreaces when the impurity is added to the substance.
JJJJJJ BBBBBB Profile
JJJJJJ BBBBBB answered
Your question is in the realm of "Freezing-point depression".  It depends on the impurity - some things raise it and some lower it.  Example: Salt raises the melting point of water.  Here is a good article on the subject: en.wikipedia.org

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