mr oxygen= 16. 16 x 3= 48
mr Al2O3= 27 + 27 + 48= 102
(48/102) X 100%= 47.05% oxygen
Answer:
The correct answer is D
Explanation:
Many substances hold their molecules together in the liquid or solid bosom. This is due, in addition to the pressure and temperature conditions, by the forces of Van der Waals. These are still produced in nonpolar molecules by the movement of electrons through the molecules; in extremely short periods of time, their electrons "charge" towards one end of the molecule, producing small dipoles and keeping the molecules very close to each other.
Just choose 3
1) Lakes can form in hollows left by meteorite impacts (e.g. Clearwater Lakes, Quebec, Canada).
2) Lakes can form in the craters formed by volcanoes (e.g. Crater Lake, Oragon)
3) Lakes can form when a river is damed by a natural rock fall or man (e.g. Lake Mede)
4) Lakes can form where glaciers have scooped out the rock from the floor of a valley (e.g. Lake Geneva)
5) Lakes can form where block faulting lowers the land (e.g. lake Baikal)
6) lakes can form in natural depressions in the land (e.g. Lake Victoria)
For the first one, you have to find one that has both a metal and a nonmetal in it, plus potassium. Bonds between nonmetals are called covalent because they share electrons and a bond between a metal and a nonmetal is an ionic bond because they exchange electrons.
Potassium chloride is KCl. Only an ionic bond.
Potassium hydride is KH. Only an ionic bond.
Potassium nitrate is KNO3. There we go, that has a covalent bond between the nitrogen and oxygen, and an ionic bond between potassium and the nitrogen and oxygen.
For the second one, potassium chloride is the answer because the other three also have covalent bonds. Chloride is the only one that isn't a compound.
