Chemistry Questions

All atoms of an element have the same number of protons. The number of protons in an element is a primary identifier known as its atomic number. The number of electrons is the same as the number of protons.

Burning gasoline is the only process that involving in a chemical change in the given options. A chemical change is a change in the starting substances that are called reactants from the formed new substances that are called products. 

There   are five known   states   of matter:    solids,    liquids,    gases, plasma and Bose-Einstein condensates.  The  main  difference in the structures of each state is in the densities of the particles.

Rust is formed from iron and oxygen.

Semiconductors are those materials that are neither good conductors nor the good insulators of heat and electricity. Silicon (Si), Germanium (Ge) and Cadmium Sulphide (CdS) are semiconductors which work as conductors in some special conditions only.