Answer:

Explanation:
At thermal equilibrium we have heat given by aluminium must be equal to the heat absorbed by the water
so we will have


so we will have

so we have

so we have


Explanation:
Echoes occur due to the reflection of sound from any obstacle, but not all the reflected sound waves lead to the phenomenon of echo. For the echo to be heard it actually depends upon the human perception as well, human ears can encounter the difference between the sound wave directly form the source and the reflected sound waves only if there is a minimum time gap of one-tenth of a second. For this time gap in the atmosphere at normal temperature and pressure the obstacle must be at least 7 meters away from the sound source.
Energy is released in the reaction
Explanation:
In a given where the energy of the products is greater than that of the reactants, we can infer that energy is released in the reaction.
This indicates that the reaction is an exothermic or exergonic reaction.
These reaction types are accompanied by release of energy.
- In an exothermic change energy is released to the surroundings.
- The surrounding becomes hotter at the end of the change.
- This applies in exergonic reaction which leaves a reaction having more energy than it originally started with.
Learn more:
Exothermic process brainly.com/question/10567109
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Answer: Option (D) is the correct answer.
Explanation:
The given elements Li, C and F are all second period elements. So, when we move from left to right across a period then there occurs increase in number of valence electrons as there occurs increase in total number of electrons.
So, it means more electrons are added to the same energy level.
Thus, we can conclude that a property of valence electrons for each element is located in the same energy level is common in the given elements.