_________ Impure water is heated till it starts to boil.
Answers
Explanation:
If the external pressure is higher than one atmosphere, the liquid will boil at a higher temperature than the normal boiling point.
Answer:
As a liquid is heated, its temperature increases. As its temperature increases, the molecules of the liquid gain energy and their kinetic energy increases. As the kinetic energy increases, the molecular motion increases and the molecules of the liquid overcome the force of attraction between them.
On continuous heating, a particular temperature is reached where the molecules of the liquid leave the surface in the form of vapour. This produces a pressure above the liquid equal to the atmospheric pressure and the liquid starts boiling.
At this stage, the temperature of the liquid remains stationary even on further heating. This stationary temperature at which the vapour pressure of the liquid is equal to the atmospheric pressure is called the boiling point of that liquid. At this temperature, bubbles begin to form and rise in the liquid. Before reaching this temperature, The bubble is not forming because the atmospheric pressure is greater than the pressure in the bubbles and they collapse.
If the external pressure is higher than one atmosphere, the liquid will boil at a higher temperature than the normal boiling point. Example: In a pressure cooker, we increase the pressure so that the pressure inside the pressure cooker is greater than one atmosphere. So the water in the cooker boils at a higher temperature and food cooks more quickly. Conversely, if the external pressure is lower than one atmosphere, the liquid will boil at a lower temperature than the normal boiling point. Example: At higher elevations, such as hills and mountains, the atmospheric pressure is lower than one atmosphere, so water boils at a lower temperature than the normal boiling point.
Types of molecules in the liquid affect the boiling point of the liquid. If the force of attraction between the molecules is relatively strong, the boiling point will be relatively high. If the force of attraction between molecules is relatively weak, the boiling point will be relatively low.
If we add impurities to a solution boiling point of the solution increases. This happens because the presence of impurities decreases the number of water molecules available to be vaporized during boiling. Once this took place, it takes a greater amount of heat to make the same amount of impure solution to vaporize as it would take to make a pure solution to vaporize, thus there would be raise in the solution's overall boiling point. It is important to realize however, that impurities do not always increase boiling point, and, in certain rarer cases, can actually cause boiling point to decrease. With this in mind, it is important to know exactly what impurities are being added to a solution in order to determine the final effect the impurities will have on boiling poin