Answer:
Large temperature and air pressure decrease.
Temperature and air pressure increase.
Explanation:
Answer:A
Explanation:
The melting points of solids depend in the relative sizes of ions in the ionic lattice. The smaller the relative sizes of the ions, the higher the lattice energy and the stronger the lattice hence higher melting point. Comparing relative ionic sizes, fluoride ion is lesser in size than chloride ion hence NaF has a higher melting point than NaCl.
A chemical change results from a chemical reaction, while a physical change is when matter changes forms but not chemical identity.
Examples of chemical changes are burning, cooking, rusting, and rotting.
Examples of physical changes are boiling, melting, freezing, and shredding.
Answer:
Option 4
Explanation:
In water molecule, oxygen has -2 charge on it while the hydrogen has +1 charge and one atom of oxygen combines with two hydrogen atoms. A hydrogen need only two electrons to complete its octet (one electron is its own the second electron is shared by oxygen) and a oxygen needs 8 electrons (It has six of its own and two are shared by two hydrogen atom).
Hence, option 4 is correct