8.98
×
N
A
cobalt atoms
Explanation:
N
A
,
Avogadro's number
specifies
6.0221
×
10
23
individual particles. It is simply another collective number like a dozen, or a score, or a gross.
N
A
has the property that
6.0221
×
10
23
individual cobalt atoms has a mass of
58.93
⋅
g
. How did I know that? Did I have it memorized?
So the quantity is
≈
54
×
10
23
cobalt atoms.
Ten name if this compound is Potassium Oxide
Answer: Option (b) is the correct answer.
Explanation:
According to the law of conservation of energy, it is known that energy can neither be created nor it can be destroyed.
But energy can be changed from one form to another.
Whereas entropy is the degree of randomness present within the molecules of a substance or object.
For example, gas molecules are able to move rapidly so, they have more entropy as compared to solid and liquid substances.
According to second law of thermodynamics, entropy of the system is always increasing.
Thus, we can conclude that "Conservation of energy" refers to the fact that energy cannot be created or destroyed but can be converted from one form to another.
The third reason helped Rutherford to discover the nucleus.
<u>Answer:</u> The correct statement is low temperature only, because entropy decreases during freezing.
<u>Explanation:</u>
The relationship between Gibb's free energy, enthalpy, entropy and temperature is given by the equation:

Where,
= change in Gibb's free energy
= change in enthalpy
T = temperature
= change in entropy
It is given that freezing of methane is taking place, which means that entropy is decreasing and
is becoming negative. It is also given that the reaction is an exothermic reaction, this means that the
is also negative.
For a reaction to be spontaneous,
must be negative.
![-ve=-ve-[T(-ve)]\\\\-ve=-ve+T](https://tex.z-dn.net/?f=-ve%3D-ve-%5BT%28-ve%29%5D%5C%5C%5C%5C-ve%3D-ve%2BT)
From above equations, it is visible that
will be negative only when the temperature will be low.
Hence, the correct statement is low temperature only, because entropy decreases during freezing.