Protons, the number of protons cannot change or the element will change as well.
Hmm.... Oxygen support combustion. Other than that, rusting occur when oxygen is combined with metal. When iron rusts, it combines with oxygen. Hope it helps.
Alcohol is completely soluble in water in any amounts. That is because every alcohol contains carbon chain and OH group which are non-polar and polar. Any substances or solutes that will be mixed with the alcohol you will just get a simple solution.
