Strong Acid cause it has a very low pH
Answer:
0.01395mol Cr2O3
Explanation:
the molar mass of Cr2O3 is 151.9904 g/mol
2.12g Cr2O3 x 1 mol/151.9904g = 0.01395mol Cr2O3
It is called a cycle because it is repetitive, therefore making it a cycle (or almost never ending)
I suppose you mean to ask why we can't go through obstacles.
Any atom is surrounded by an electronic cloud. When two atoms get close to each other, the electronic clouds repel each other, preventing them from interpenetrating each other. That same phenomenon, on a larger scale, prevents us from going through matter.
Answer:
For the wavelenth of light spectrum, I believe the order would be red visible light, infrared, microwaves and radio waves.