Answer:
b) Counter current
Explanation:
In mechanical, chemical, nuclear and other systems, it happens that heat must be transferred from one place to another or from one fluid to another. Heat exchangers are the devices that allow you to perform this task the types of exchangers are presented of heat as a function of flow: parallel flow; <u>counterflow</u>; cross flow.
Among the main reasons why exchangers are used
Heat are as follows:
• Heat a cold fluid using a fluid with a higher temperature.
• Reduce the temperature of a fluid by means of a fluid with a lower temperature.
• Bring the fluid to the boiling point using a fluid with a higher temperature.
• Condense a fluid in a gaseous state by means of a cold fluid
A backflow occurs when the two fluids flow in the same direction but in opposite way. Each of the fluids enters the exchanger through different ends Since the fluid with less temperature goes backflow from the heat exchanger at the end where the fluid enters with higher temperature, the temperature of the coldest fluid will approach the temperature of the inlet fluid.
This type of exchanger turns out to be more efficient than the other two types mentioned above. In contract with the exchanger parallel flow heat, the counterflow exchanger may have the highest temperature in the cold fluid and the lower temperature in the hot fluid after heat transfer in the exchanger.
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Be careful with </em><u><em>turbulent</em></u><em> that it is not a type of exchanger but a system in which a fluid is found.</em>
Answer:
1) Dispersion forces: It is a type of force which is present between atoms and molecules. It is a weakest intermolecular force that occurs between atoms. It is also called induced dipole-induced dipole attraction.
2. Dipole-dipole: It is a type of attractive force which is present between the negative end of one molecule with the positive end of another molecule. This type of attractive force occurs between polar molecules.
3) Hydrogen bond: It is a type of electromagnetic force which is present between hydrogen and high electronegative atoms such as nitrogen and oxygen etc.
Answer : The correct answer is a) an exothermic reaction that releases energy.
Combustion reaction is generally referred as burning or when hydrocarbon reaction with oxygen to produce carbon dioxide and water . Combustion reaction releases energy. Example :
CH₄ + O₂ → CO₂ + H₂O + Energy or heat .
The reaction which releases energy or heat are known as Exothermic reactions .
Since it says hot dogs and hamburgers are cooked means they are undergoing combustion chemical reaction and so they are exothermic reactions. So option a) an exothermic reaction which releases energy is correct .
