Answer:
C.proust
Explanation:
Proust's law of definite proportions.
Answer:
2
Explanation:
The compounds XCl₂ and X₃N₂ shows that the valency of X is 2. If they are ionic compounds then X is a metal. The metals having valency=2 mostly reside in group-2.
Oxygen carbon and hydrogen
Answer : The correct option is, ![8.988\times 10^{-26}joules](https://tex.z-dn.net/?f=8.988%5Ctimes%2010%5E%7B-26%7Djoules)
Solution :
Formula used :
![E=\frac{h\times c}{\lambda}](https://tex.z-dn.net/?f=E%3D%5Cfrac%7Bh%5Ctimes%20c%7D%7B%5Clambda%7D)
where,
E = change in energy
h = Planck’s constant = ![6.626\times 10^{-34}J/s](https://tex.z-dn.net/?f=6.626%5Ctimes%2010%5E%7B-34%7DJ%2Fs)
c = speed of light = ![2.998\times 10^{8}m/s](https://tex.z-dn.net/?f=2.998%5Ctimes%2010%5E%7B8%7Dm%2Fs)
= wavelength = 2.21 m
Now put all the given values in the above formula, we get the energy of an atom.
![E=\frac{(6.626\times 10^{-34}J/s)\times (2.998\times 10^{8}m/s)}{2.21m}](https://tex.z-dn.net/?f=E%3D%5Cfrac%7B%286.626%5Ctimes%2010%5E%7B-34%7DJ%2Fs%29%5Ctimes%20%282.998%5Ctimes%2010%5E%7B8%7Dm%2Fs%29%7D%7B2.21m%7D)
![E=8.988\times 10^{-26}joules](https://tex.z-dn.net/?f=E%3D8.988%5Ctimes%2010%5E%7B-26%7Djoules)
Therefore, the energy of an atom is, ![8.988\times 10^{-26}joules](https://tex.z-dn.net/?f=8.988%5Ctimes%2010%5E%7B-26%7Djoules)
Answer:
true
Explanation:
you can't change it back, it's chemically changed