El mol es definido como la cantidad de materia que contiene determinado número de entidades elementales (átomos, moléculas, etc.) equivalente a la cantidad de átomos que hay PASAR DE GRAMOS A MOLES

A. tenemos 250 g de hierro, ¿Cuántas moles de hierro están contenidos en dicha masa?

a.
4,46 Moles

b.
4,87 Moles

c.
3,76 Moles

answer is: c. the experiment shows that the red substance experienced a chemical change.

this is chemical change (chemical reaction), because two new substances are formed (metalig liquid and gas), the atoms are rearranged and the reaction is followed by an energy change.

this is example of chemical decomposition.

chemical decomposition (analysis) is the separation of a single chemical compound into its two or more elemental parts or to simpler compounds.  

chemical decomposition is opposite of chemical synthesis.

the answer is yes

it has kinetic energy

reason

an object has kinetic energy when you stop the force carrying it, the object will stay in motion.

hope this contact me for more questions if you'd like: )