Concentration is the amount of substance per defined space. Another definition is the ratio of solute in a solution to either solvent or total solution. :)
The answer is A, I hope this helps
<span>Gravity is a very important force. Every object in space exerts a gravitational pull on every other, and so gravity influences the paths taken by everything traveling through space. It is the glue that holds together entire galaxies. It keeps planets in orbit. It makes it possible to use human-made satellites and to go to and return from the Moon. It makes planets habitable by trapping gasses and liquids in an atmosphere. It can also cause life-destroying asteroids to crash into planets.</span>
Bonding and antibonding molecular orbitals where the sigma bonding molecular orbital has 2 electrons
Warmer atoms expand. There is also more movement. This is also explained when putting it into terms with solid vs. gas. in a solid, the atoms vibrate, but they can't move very far because there is not a lot of space between them. In a gas, on the other hand, the atoms are spread apart, and they move very fast. Putting it into context with water, the steam (gas) version is hot, and the ice cube (solid) version is cold.