8. 4 grams of water will be produced.
Kinetic Molecular Theory states that gas particles are in constant motion and exhibit perfectly elastic collisions.
The compound formed by chlorine and barium is 
as the number of valence electrons in barium is 2 and in chlorine is 1. In this compound, barium acts as a cation and chlorine acts as an anion. The formation of the compound is as shown in the image.
Since, barium is an element of Group-2 (alkaline earth metal) so the other element that has a chemical formula most and least similar to the chemical formula of the compound formed by chlorine and barium should be from Group-2 (alkaline earth metal) only which has properties somewhat like barium. So, the element is strontium.
Strontium forms a compound with formula 
in which strontium acts as a cation and chlorine acts as an anion. The formation of the compound is as shown in the image.
Answer:
Gravitional Force
Explanation:
Every planet has a gravitational pull which attracts all objects; the moon is no exception. It says forces in the question but I know for sure gravitational force is apart of it.
Blocks of magnesium is used to prevent iron corrosion.
This way of prevention is called sacrificial protection.
