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Specific heat capacity, pronounced b rè róng, Specific Heat Capacity in English, refers to the amount of heat required to raise the temperature of 1 g of homogeneous substance by 1 K without phase change and chemical change.
Specific heat capacity
- The specific heat capacity (specific heat) of a substance of a certain mass when the temperature increases is the ratio of the amount of heat absorbed to the product of the mass of the substance and the increased temperature, which is denoted by c. its
- The unit of specific heat capacity is a composite unit.
- in
- There is an object with mass m. When the heat Q is absorbed (or released) in a certain process, the temperature rises (or decreases) T, then Q / T is called the object's temperature in this process.
- During the experiment, the constant pressure specific heat capacity of liquid water is often used to calculate the heat absorbed or emitted. Water is the most common substance, and its specific heat data is easier to obtain. When the accuracy of the experiment is not high, it can be approximated as The constant pressure specific heat of water under normal pressure is 4.2kJ / KG. ,
- The specific pressure specific heat capacity Cp of liquid water at different pressures and temperatures is given below (unit: KJ / (KG. ))
| Temperature (Celsius) | ||||||||
| 0 | 20 | 50 | 100 | 150 | 200 | 250 | 300 | 350 | |
| 1 | 4.217 | 4.182 | 4.181 | ||||||
| 5 | 4.215 | 4.181 | 4.180 | 4.215 | 4.310 | ||||
| 10 | 4.212 | 4.179 | 4.179 | 4.214 | 4.308 | ||||
| 50 | 4.191 | 4.166 | 4.170 | 4.205 | 4.296 | 4.477 | 4.855 | 3.299 | |
| 100 | 4.165 | 4.151 | 4.158 | 4.194 | 4.281 | 4.450 | 4.791 | 5.703 | 4.042 |
| 150 | 4.141 | 4.137 | 4.148 | 4.183 | 4.251 | 4.425 | 4.735 | 5.495 | 8.863 |
| 200 | 4.117 | 4.123 | 4.137 | 4.173 | 4.252 | 4.402 | 4.685 | 5.332 | 8.103 |
| 250 | 4.095 | 4.109 | 4.127 | 4.163 | 4.239 | 4.379 | 4.639 | 5.201 | 7.017 |
| 300 | 4.073 | 4.097 | 4.117 | 4.153 | 4.226 | 4.358 | 4.598 | 5.091 | 6.451 |
- For a substance of unit mass, the amount of heat released by decreasing the temperature by 1 degree is equal to the amount of heat absorbed by the increase of its temperature, and is also numerically equal to its specific heat capacity.
- The specific heat capacity of water is large, and it is widely used in industrial and agricultural production and daily life. This application mainly considers two aspects. The first is that a certain amount of water absorbs (or emits) a lot of heat, but its temperature does not change much, which is conducive to climate adjustment. The second is that a certain amount of water rises (or decreases). A lot of heat is absorbed (or exothermic) at a certain temperature, which is conducive to using water as a coolant or heating.
- Originally in the 18th century, Scottish physicist and chemist J. Black discovered that different substances of the same mass have different amounts of heat to reach the same temperature, and proposed the concept of specific heat capacity. Specific heat capacity can be measured for almost any substance, such as chemical elements, compounds, alloys, solutions, and composite materials.
- Historically, the specific heat capacity of water was used to define calories, and the amount of heat required to raise 1 gram of water by 1 degree was defined as 1 calorie.