We can define a calorie as the amount of energy required to raise one gram of water by one degree Celsius. It is important to remember that this value can vary. For instance, a 100 W light bulb releases 100 joules of energy per second. But if the temperature of the water is changed by a single degree Celsius, the calorie can increase to 200W. The same goes for an olympic long jumper, who can reach 2500W!
When a substance changes state, it must release heat energy to separate its molecules. This energy is called LATENT HEAT. Solids and liquids are not heated during the process. The temperature only changes when the change in state has occurred. This amount of heat is called SPECIFIC LATENT HEAT. The units for specific latent heat are joules per kilogram.
A substance can change state when it encounters heat energy. Heat is used to separate molecules, and the amount of energy needed to transform one kilogram of a substance is called SPECIFIC LATENT HEAT. Specific latent heat is the amount of heat needed to change the state of one kilogram. The units for this type of heat are joules/kg. This is an important unit to understand in order to understand how many joules you need to produce one gram of a substance.
The amount of heat required to change one gram of a substance depends on the material. The density of a substance is dependent on how much energy is required to change the state. For example, liquids need more energy than solids. The amount of heat required to make a one gram of a certain substance change state is called SPECIFIC LATENT HEAT. In chemistry, this energy is expressed in joules per kilogram.
A substance can release different types of energy during a chemical reaction. For instance, a gaseous substance releases more energy than a solid, and a liquid is more dense than a solid. The density of a substance depends on the type of gaseous substance. A liquid is a mix of two substances. A mixture of a liquid will have a lower density than a solid.
For a solid to change state, a reaction produces heat energy. If a liquid changes state, it releases chemical energy. For a solid, the temperature only changes when the change is complete. The same is true for a gas. However, a gas contains the same amount of energy as a solid, so it is important to consider the specific latent heat of a liquid.
For a liquid, 0.06 kilograms of air will release 0.6 MJ. This means that the reaction requires the release of heat energy. The higher the pressure, the more energy the substance will change. A 1.3 MJ substance will be released by a 0.4 kg liquid. Its density also reflects the density of a liquid. The higher the temperature, the more pressure it will create.
When a solid changes state, heat energy is required to separate its molecules. This energy is called LATENT HEAT. For a liquid, the amount of heat required to change state is referred to as SPECIFIC LATENT HEAT. This is the amount of heat required to change a single kg of a substance. This energy is measured in joules.
A kilogram of water releases 3.6 MJ of heat energy. A kilo of water can lose more than 106 MJ of energy per kilometer. In the case of a solid, the specific latent heat required to change state of a liquid is 2.26 kWh/kg. This is the energy required to move one kilo of a substance from one state to another.