Fossil fuels are mostly the major source of energy
Well the group fluorine is in is known as Halogens. Halogens all have seven valence electrons in their outer shell. They exist as diatomic molecules. Furthermore they readily combine with metals to form salts
Answer: Yes the statement is true.
Explanation: Endorphins are chemicals produced by the human bodies to relieve stress and pain.
They are produced mainly by brain and help to transmit electrical signals within nervous system, thus are called as neurotransmitters.
They are also called as "feel good chemicals" as they can act as pain relievers and happiness booster and thus lead to better emotional health.
Answer:
b. Heat flows from the surroundings to the system and the temperature of the water decreases.
Explanation:
The laws of thermodynamics lets us know that energy is neither created nor destroyed but can be converted from one form to another. Also, energy transfer does accompany chemical reactions in the form of heat.
For an endothermic reaction, heat is absorbed by the system from the surroundings. This leads to a drop in the temperature of the surroundings as energy is removed.
This implies that the water temperature decreases.
1.59moles
Explanation:
Mass of CaO = 89.23g
Unknown
Number of moles = ?
Solution:
The mole is a unit of measurement in chemistry used to delineate the number of particles an atom contains.
A mole of a substance contains the avogadro's number of particles.
Number of moles = 
Molar mass of CaO = 40 + 16 = 56g/mol
Number of moles = 
= 1.59moles
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Number of moles brainly.com/question/1841136
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