Answer:
Explanation:Energy is the capacity of a physical system to perform work. Energy exists in several forms such as heat , kinetic or mechanical energy, light, potential energy , electrical, or other forms. Energy is the ability to do work. Energy sources could be classified as Renewable and Non-renewable.
Answer:
Strontium
Explanation:
The atomic number of strontium is 38.
It has 38 electrons.
It is alkaline earth metal. It has two valance electrons.
Strontium loses its two electrons and form cation with +2 charge.
Electronic configuration;
Sr₃₈ = [Kr] 5s²
The valance electrons present in 5s are lost by strontium atom and form Sr⁺² cation.
it is yellowish-white metal.
It is highly reactive.
It form salt with halogens.e.g
Sr + Br₂ → SrBr₂
IT react with oxygen and form oxide.
2Sr + O₂ → 2SrO
this oxide form hydroxide when react with water,
SrO + H₂O → Sr(OH)₂
With nitrogen it produced nitride,
3Sr + N₂ → Sr₃N₂
With acid like HCl,
Sr + 2HCl → SrCl₂ + H₂
While the material retains its chemical makeup, the physical property may be examined. The given statement is true.
The matter can undergo variations in physical or chemical properties. The physical changes of a matter occur when the matter undergoes changes in its physical properties like changes in the state of matter, weight, color, etc.
But the chemical composition of matter will remain constant if it undergoes a physical change. Whereas in chemical change, the matter undergoes a change in the composition of the substance but there will be no change in the physical properties.
Hence, The assertion is correct in that physical properties can be seen while the substance's chemical makeup stays constant.
To learn more about physical and chemical change, visit: brainly.com/question/21509240
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Most of the surface of the earth is covered with water and looks blue from space.
