Answer:
0.9715 Fraction of Pu-239 will be remain after 1000 years.
Explanation:


Where:
= decay constant
=concentration left after time t
= Half life of the sample
Half life of Pu-239 =
[
![\lambda =\frac{0.693}{24,000 y}=2.8875\times 10^{-5} y^{-1]](https://tex.z-dn.net/?f=%5Clambda%20%3D%5Cfrac%7B0.693%7D%7B24%2C000%20y%7D%3D2.8875%5Ctimes%2010%5E%7B-5%7D%20y%5E%7B-1%5D)
Let us say amount present of Pu-239 today = 
A = ?
![A=x\times e^{-2.8875\times 10^{-5} y^{-1]\times 1000 y}](https://tex.z-dn.net/?f=A%3Dx%5Ctimes%20e%5E%7B-2.8875%5Ctimes%2010%5E%7B-5%7D%20y%5E%7B-1%5D%5Ctimes%201000%20y%7D)


0.9715 Fraction of Pu-239 will be remain after 1000 years.
- Endothermic reaction means the reactant side takes heat from surrounding and get decomposed i.e ∆H=-ve
- If the equation is exothermic then it means the reactant is happy to decompose .But it's not as it's endothermic
Now
- HgO is Omitted from our solution option.
Hg is a atom so no bonds hence no bond strength occurs.
- O_2 is a molecule and so it's our answer .
Answer:
electron cloud charge of manganese=-5
Explanation:
atomic number=number of elecron +neutron number
DATA
Neutron NO.=30
atomic NO.=25
e=?
A=e+n
25=e+30
e=25-30
e= -5
you calculate all the letters together and it would be Zn2
The quantity of heat required to vapourize 1 mole of a substance depends on the kind of intermolecular forces between the molecules of the substance. Diethyl ether molecules are held together by weak dispersion forces compared to the stronger hydrogen bonding in ethanol. Therefore, 1 mole of diethyl ether requires less heat to vapourize than is required to vapourize 1 mole of ethanol.
Intermolecular forces hold the molecules a substance together in a given state of matter. The properties of a substance such as boiling point, melting point etc are dependent on the nature of intermolecular forces holding the molecules of the substance.
Diethyl ether molecules are held together by weak dispersion forces while molecules of ethanol are held together by hydrogen bonds.
Since hydrogen bonds are much stronger than dispersion forces, a greater quantity of heat is required to break the intermolecular hydrogen bonds in ethanol in order to vapourize them than is required to vapourize diethyl ether.
Therefore, owing to stronger intermolecular forces between molecules of ethanol, less heat is required to vapourize than is required to vapourize 1 mole of ethanol.
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