Explanation:
When two small nuclei combine together to form a large nuclei then it is known as nuclear fusion.
When nuclei of two hydrogen atoms fuse together then it results in the formation of a helium atom along with the release of lot of energy. This energy is nuclear energy.
This nuclear reaction is as follows.

Thus, we can conclude that nuclear fusion represents nuclear energy.
Answer:
Both are chemical changes.
Explanation:
They are chemical changes because when when you melt the sugar to make caramel a new substance is formed. The same with cookies. You don't start out with cookies, you start out with dough. And then when you cook the dough a new substance is formed which is the cookies.
<u>Answer:</u> For the given amount of sweat lost, the amount of energy required will be 692,899 Joules.
<u>Explanation:</u>
We are given:
Heat of vaporization for water = 2257 J/g
Amount of sweat lost = 307 grams
Applying unitary method:
For 1 g of sweat lost, the energy required is 2257 Joules
So, for 307 grams of sweat lost, the energy required will be = 
Hence, for the given amount of sweat lost, the amount of energy required will be 692,899 Joules.
Explanation:
The equation is given as;
N2O(g) ⇄ N2(g) + O(g)
k₁ = Forward reaction
k₋₁ = Reverse Reaction
Equilibrium concentration (K) = k₁ / k₋₁
![K = \frac{[N2O] }{[N2] [ O]}](https://tex.z-dn.net/?f=K%20%3D%20%5Cfrac%7B%5BN2O%5D%20%7D%7B%5BN2%5D%20%5B%20O%5D%7D)
Electronegativity is the tendency of an element to attract the bonded electrons towards itself. In a group, as the atomic radius increases electronegativity decreases as the outermost electron is far away from the nuclear attraction. In a period, the atomic size decreases. So, the effective nuclear charge experienced by the outermost shell increases. Therefore, across a period the electronegativity increases as the increased effective nuclear charge leads to the attraction of bonded electrons with greater ease.
Therefore the correct answer is <u>c</u>, electronegativity tends to increases across a period.