The coefficient of performance (cop) of a refrigerator is defined as the ratio of " the work necessary to heat or cool something usefully."
The usable heating or cooling delivered to work required ratio, also known as the coefficient of performance, or COP, of a heat pump, refrigerator, as well as air conditioning system. Higher efficiency, less energy (power) usage, and thus reduced operational costs are all related to higher COPs.
Coefficient of performance formula:

where, K = Coefficient of performance,
= heat of pumps output,
= work required by the system.
It is refrigeration's coefficient of performance (COP) will always be greater than 1.
Therefore, the coefficient of performance (cop) of a refrigerator is defined as the ratio of " the work necessary to heat or cool something usefully."
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The volume did not change, it remained at 20 ml
<h3>Further explanation</h3>
Given
20 ml a sample gas at STP(273 K, 1 atm)
T₂=546 K
P₂=2 atm
Required
The volume
Solution
Combined gas Law :

Input the value :

The volume does not change because the pressure and temperature are increased by the same ratio as the initial conditions (to 2x)
This is an example of displacement reaction
<u>Explanation:</u>
- The chemical reaction in which the one element replaces the other element in a compound is called a displacement reaction. This reaction is also called a replacement reaction.
AB + C -----> AC +B
2ZnS + 3O2 -----> 2ZnO + 2SO2
- This happens when A is more reactive than B and gives a stable product. Here the zinc sulfide compound reacts with the oxygen element to the stable product of zinc oxide and sulfur dioxide.
- In short, the more reactive element displaces the less reactive element is called a displacement reaction.
Nonmetals form negatively charged ions, or anions. They do this because they need to gain one to three electrons in order to achieve an octet of valence electrons, making them isoelectronic with the noble gas at the end of the period to which they belong.