Answer:
B) 2Crº + 6e- --> 2Cr3+
Explanation:
The process of oxidation is where electrons are lost. Thus, out of the 2 ions that change charge(Cr and Cu), we must choose the one where the oxidation number increases(which means electrons are lost). Cr goes from an oxidation number of 0 to an oxidation number of 3+, while Cu goes from an oxidation number of 2+ to 0. Thus, we are looking at the half reaction for Cr. Half reactions never have subtracting electrons, so the answer must be B. I am assuming that last plus should be a -->
Answer:
Mass = 9.58 g
Explanation:
Given data:
Mass of Fe₂O₃ formed = ?
Mass of Fe = 6.7 g
Solution:
Chemical equation:
4Fe + 3O₂ → 2Fe₂O₃
Number of moles of Fe:
Number of moles = mass/molar mass
Number of moles = 6.7 g/ 55.8 g/mol
Number of moles = 0.12 mol
now we will compare the moles of Fe and Fe₂O₃.
Fe : Fe₂O₃
4 : 2
0.12 : 2/4×0.12 = 0.06 mol
Mass of Fe₂O₃:
Mass = number of moles × molar mass
Mass = 0.06 mol × 159.69 g/mol
Mass = 9.58 g
