Explanation:
A fusion reaction is a reaction in which two or more small nuclei combine together to form a larger nuclei.
As it is known that a nucleus contains protons and neutrons. So when nuclei of two atoms combine together then there will be repulsion between the protons due to the presence of like charges. As neutrons have no charge so there will be no attraction or repulsion between neutrons of two nuclei.
Thus, we can conclude that in a fusion reaction, a major problem related to causing the nuclei to fuse into a single nucleus is the repulsion of nuclei.
Answer:- 71.7 calories
Solution:- it is a unit conversion problem where we need to convert joules into calories.
The unit conversion for these energy units is:
1 calorie = 4.184 joule
The given energy is 300 joules and has to be converted to calories. We will show the set up using dimensional analysis.

= 71.7 calories
So, the energy in calories is 71.7.
Answer:

Explanation:
Group 4A contains a total of 4 electrons for each atom in their valence shell. Filling the orbital diagram, let's say, for carbon, notice that when we start with period 2, we have two elements in the s-block, that is, lithium and beryllium. They correspond to the two s electrons that belong to the valence shell of carbon.
Moving on, we have boron and carbon, the remaining 2 electrons. Now, starting with boron, we're in the p-block.
That said, looking at the second period, the electron configuration for the valence shell of a group 4A element would be:

Volume of Hydrogen V1 = 351mL
Temperature T1 = 20 = 20 + 273 = 293 K
Temperature T2 = 38 = 38 + 273 = 311 K
We have V1 x T2 = V2 x T1
So V2 = (V1 x T2) / T1 = (351 x 311) / 293 = 372.56
Volume at 38 C = 373 ml