Ce procent de impuritati contine un minereu de siderit, daca din 1500kg minereu s-au obtinut 700kg fier 90% ?

It has 12.84% of impurity

Explanation:

You obtained 700 kg 90% purity of Fe, so you have:

Those 630 kg are the mass of Fe contained in the original sample of 1500 kg in the from of Siderit.

The other substeances that aren't Siderit in the sample can be considered impurities.

Siderit:

The mass of siderit:

Percentaje of impurity:

nacl or sodium chloride is an ionic compound. this is because an ionic compound pertains to a compound that consists of positively and negatively charged ions. in this case, na (sodium) has a tendency to lose one electron when it reacts with with other atoms, so the resulting sodium ion contains 11 protons and 10 electrons, thus making it positively charged (na+), when chlorine reacts, it usually gains one electron to form an ion called chloride, thus making it negatively charged ( since the ions are oppositely charged, they attract.