You can tell that a crystal is a crystal if it creates a rainbow prism effect. Or you can tell by tapping the crystal. If he crystal makes a musical ring noise (like how a glass cup would sound) it’s a crystal.
Answer and Explanation:
The explanation given in the problem is correct but not totally encompassing.
Van der waals interactions are a type of hydrophobic interaction, in which they do not interact with the polar water molecule. Covalent bonds involve the sharing of electrons between atoms of relatively similar electronegativities, and are most often too strong to disrupt by polar molecules of water. Therefore, covalent bonds and van der waals forces have an Intrinsic bond strength value that is independent of the environment.
However, either the partial negative oxygen atom or the partial positive hydrogen atoms in water molecules disrupt hydrogen or ionic bonds. Water is known to form hydrogen bonds with other polar or charged molecules, thus reducing the strength of interaction these molecules would normally have in the absence of water. Basically, these compounds with Hydrogen or Ionic bonds ionize, whether partially or fully in water, thereby leading to a decrease in bond strength in water.
QED!
Here is your answer:
The crust and uppermost mantle make up the rigid outer layer of Earth, which is called the "lithosphere." The crust and the mantle makes up the lithosphere. The lithosphere is rigid outer part of the earth which contains the upper mantle and the crust.
Hope this helps!
<em>~Nonportrit</em>
Answer:
Mass of He required = 8.0 g
Explanation:
Given,
Initial moles of He = 2.0 mol
Initial pressure = 1.00 atm
final pressure = 2.00 atm
Ideal gas equation,
PV = nRT
As V, R and T are constant
So, 
Molar mass of He = 4.00 g/mol
No. of moles of He needs to be added = 4.0 - 2.0 = 2.0 mol
Mass = No. of mole × Molar mass
= 2.0 × 4.0
= 8.0 g
