9. Equations for reactions of iron and iron compounds are shown. Fe + 2HCl → FeCl2 + H2
2FeCl2 + Cl2 → 2FeCl3
FeSO4 + Mg + Fe + MgSO4
FeSO4 + 2NaOH → Fe(OH)2 + Na2SO4
How many of these are redox reactions?
A 1
B 2
С 3
D 4

Between 2014 and 2016, more than 25,000 children in flint, michigan, drank water that was contaminated with lead from lead pipes. during this time, the city claimed the water was safe to drink. which of these actions could the city have taken to ensure that the drinking water was free from lead?

To apply in a gold the individual gold atoms are united to each other by means of a metallic bond. how would you use the gold block to determine the atomic radius of a gold atom?

One nanometer is equal to how many meters?