¿Toda sustancia de aspecto homogéneo es siempre una sustancia pura?

En química, un sistema homogéneo es aquel sistema material que presenta las mismas  Una sustancia pura es un sistema homogéneo a partir del cual no es posible obtener otras  para aislar a un sistema del medio y siempre habrá intercambio o de materia o de energía; el más perfecto es el frasco de Dewar.

Explanation:

explanation:

with the profits from the european sales, merchants purchased europe's manufactured  goods, including tools and weapons. then the merchants shipped those manufactured  goods, along with the  american  sugar and rum, to west africa where they were bartered for  slaves.

for many centuries there were important factors which the economies of the muslim empires developed increasingly. they applied economic procedures in production, investment, finance, taxation and property. they used to tax certain goods (for example: harvest), they charged interest on money lent, they signed contracts with merchants; they relied on a common currency, and they used checks as well as promissory notes. with the money collected by means of taxation, the government provided the needy with an income. in addition, trading networks covered huge distances, so far regions started to have contact and exchange goods. this trade network covered areas of asia, africa and europe.