What water has 97% of water

pure water does not conduct electricity very well. however, when certain substances are dissolved in water, the solution does conduct electricity. you can make a simple device that shows how well a solution conducts electricity. this device uses a flashlight bulb to indicate how well the solution conducts electricity. the better the solution conducts electricity, the brighter the bulb will glow.

explanation:

i believe you are right for all except the 3rd ( look at sqdancefan his answer is much better)

a compound is a molecule made of atoms from different elements.

a. by the combination of an unlimited number of elements

o conteúdo de calor de um sistema é igual à entalpia apenas para um sistema que é constante