| Aim | To determine the melting point of ice and boiling point of water. |
| Theory | Melting Point: Melting point is the temperature at which a solid substance transitions into a liquid state at a given atmospheric pressure. It is a physical property of a substance and is usually determined by heating a sample of the substance until it melts completely. The melting point of a substance is typically reported as a range of temperatures, as different samples of the same substance may have slightly different melting points due to impurities or other factors. The melting point can be used to identify a substance or to assess its purity, as pure substances generally have a sharp melting point while impure substances have a broader melting point range. Boiling Point: Boiling point is the temperature at which the vapor pressure of a liquid equals the atmospheric pressure, causing the liquid to transition into a gas state. The boiling point of a substance is dependent on the pressure of the surrounding environment, with higher pressures resulting in higher boiling points. Boiling point is a physical property of a substance and can be used to identify a substance or to assess its purity, as pure substances generally have a sharp boiling point while impure substances have a broader boiling point range. Boiling point is also used in various applications such as distillation, where different substances can be separated based on their boiling points, as each substance will vaporize and condense at different temperatures. Latent Heat of Fusion :Latent heat of fusion is the amount of heat energy required to change a substance from a solid state to a liquid state without any change in temperature. During this process, the heat energy is absorbed by the substance to overcome the attractive forces between its molecules and to separate them from their fixed positions in the solid lattice structure. As a result, the temperature of the substance remains constant even though heat is being added. The latent heat of fusion is a physical property of a substance and is measured in units of energy per unit mass, such as joules per kilogram (J/kg) or calories per gram (cal/g). The value of the latent heat of fusion varies for different substances, and it is generally higher for substances with stronger intermolecular forces between their molecules. The latent heat of fusion plays an important role in various applications, such as in refrigeration and freezing processes, as well as in the formation of snow and ice. Latent Heat of Vaporization :Latent heat of vaporization is the amount of heat energy required to change a substance from a liquid state to a gas state without any change in temperature. During this process, the heat energy is absorbed by the substance to overcome the attractive forces between its molecules and to separate them from their neighboring molecules in the liquid state. As a result, the temperature of the substance remains constant even though heat is being added. The latent heat of vaporization is a physical property of a substance and is measured in units of energy per unit mass, such as joules per kilogram (J/kg) or calories per gram (cal/g). The value of the latent heat of vaporization varies for different substances, and it is generally higher for substances with stronger intermolecular forces between their molecules. The latent heat of vaporization plays an important role in various applications, such as in steam engines, power generation, and distillation processes, as well as in natural phenomena such as the water cycle and cloud formation. |
| Apparatus Required | Two thermometers, (Celsius scale), boiling tube, a glass rod, two iron stands, a Bunsen burner, wire gauze, beakers, tripod stand, distilled water, ice cubes prepared from distilled water. |
| Procedures | ||
| (A)To determine the boiling point of water. | 1 . Begin the experiment by adding a few pumice stones to 25-30 ml of water in a boiling tube. 2 . Secure the boiling tube to an iron stand using a two-holed cork, with a thermometer and delivery tube in each hole, respectively. 3 . Position the thermometer above the water in the flask, following the diagram, and note the temperature. Place a burner beneath the boiling tube. 4 . Monitor and record the temperature readings in the observation table every minute until the water boils. |  |
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| (B)To determine the melting point of ice. | 1 .Take a beaker half-filled with the dry crushed ice obtained from distilled water. 2 .Suspend a Celsius thermometer from the clamp stand such that the bulb of the thermometer is completely surrounded by ice. 3 .Read the thermometer reading and record the temperature after every 1 minute till the ice melts and the thermometer reading remains stationary for 2 minutes. 4 .Note the readings in the observation table. |  |
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