Answer:
Initially, the ballast tanks are filled with water. The weight of the submarine is equal to the upthrust of the water at the position of the submarine under water. When high pressure air is released into the ballast tanks displacing the water, the weight of the submarine becomes less than the upthrust of the water thus the net force is is upwards and it forces the sub to resurface. This is according to the Archimedes principle which states that a a body partially or wholly immersed in water displaces its own weight of the fluid in which it is immersed.
<h2>Answer:</h2>
The density of mercury molecule is higher than water.
<h3>Explanation:</h3>
Density is defined as mass per unit volume.In other words, density is the amount of matter within a given amount of space. water has the density of 1.0 gram per milliliter whereas the mercury has a density of 13.6 grams per centimeter squared.
One reason for the differences in density between mercury and water is that the atomic mass of mercury is 200.59 grams per mole. The atomic mass of water is 18.0 grams per mole. This is because mercury has a larger nucleus than hydrogen or water.
Additionally, there are strong inter-molecular forces (hydrogen bonds) between water molecules. hydrogen molecules do not stack upon one another as nicely as mercury atoms. Thus, there is additional empty spaces between the water molecules leading to its lower mass per volume(density)
Answer:
Covalent
Explanation:
A molecule of C₂H₅OH has C-C, C-H, C-O, and O-H bonds.
A bond between A and B will be ionic if the difference between their electronegativities (ΔEN) is greater than 1.6.

No bond has a large enough ΔEN to be ionic.
C₂H₅OH is a covalent molecule.
<h2>Answer:</h2>
Option D is correct. It is independent of the reaction pathway.
<h2>Explanations:</h2><h2>What is Hess's law?</h2>
Hesslaw states that the enthalpy change of a reaction does not change regardless whether the reaction takes place in a single or multiple reaction pathways.
This shows that the total entalpy change of a reaction does not depend on the reaction pathway.