Artikel Kimia

---

What is Freezing Point Posted: 04 Feb 2012 07:36 AM PST The freezing point of a liquid is the temperature at which it changes from a liquid to a solid, the terms freezing point and melting point are synonymous. As a liquid loses heat energy, its temperature drops, molecules move more and more slowly and intermolecular forces of attraction predominate. If enough heat energy is lost, the liquid assumes the characteristics of a solid; for example, as heat is removed from water, it will freeze into a solid (ice). Every Liquid has a characteristic freezing point. The amount of heat energy required to change 1 gram of a substance from a solid to a liquid as its freezing (melting) point is called its heat of fusion.

What is Boiling Point Posted: 03 Feb 2012 08:33 PM PST On the surface of every liquid, a few wmolecules will always break through the surface tension, escape the liquid and rise into the surrounding air as gaseous molecules. This change of state -form a liquid to a gas – in the surface molecules is called evaporation. The vapor of a liquid is a measure of its tendency to evaporate. Every liquid has a characteristic vapor pressure that changes as the internal temperature of the liquid changes; generally as the temperature of a liquid increases, its vapor pressure also increases. The boiling point of a liquid is the temperature at which its vapor pressure equals the pressure equals the pressure of the surrounding air; at this temperature, molecules within the liquid form gaseous bubbles that rise to the surface and escape into the surrounding air. The addition of heat energy raises the temperature of a liquid; it also causes a drop in the temperature of a liquid; it also causes a drop in the intermolecular forces attraction between liquid molecules as well as a drop in the liquid’s viscosity and surface tension. As the temperature of a liquid rises, its molecules become increasingly jostled, moving more and more rapidly; this allows more molecules to escape (evaporate) from the liquid’s surface. Every liquid has a characteristic boiling point The boiling point of a liquid changes with atmospheric pressure; as the atmospheric pressure decreases, the boiling point also decreases. The amount of heat energy required to change 1 gram of a substances from a liquid to a gas as its boiling point is called its heat of vaporization. When heat energy is lost from a gas, molecules may return to their liquid state in a process called condensation, which is the opposite of evaporation

You are subscribed to email updates from Artikel Kimia To stop receiving these emails, you may unsubscribe now.	Email delivery powered by Google
Google Inc., 20 West Kinzie, Chicago IL USA 60610