A, O2 has to be a reactant for combustion to burn
Answer:
See explanation
Explanation:
The balanced redox reaction equation is;
8H+ + MnO4^- + 5Fe2+ ---------> Mn2+ + 5Fe3+ + 4H2O
Amount of KMnO4 reacted = 31.60/1000 * 0.05120 = 1.62 * 10^-3 moles
From the reaction equation;
1 mole of MnO4^- reacted with 5 moles of Fe2+
1.62 * 10^-3 moles will react with 1.62 * 10^-3 moles * 5/1 = 8.1 * 10^-3 moles
Mass of Fe2+ reacted = 8.1 * 10^-3 moles * 56 g/mol
Mass of Fe2+ reacted = 0.45 g
Amount of iron in the sample = 0.45 g
Percentage of iron in the sample;
0.45 g/4.230 g * 100 = 10.6 %
Answer:
2C₃H₇BO₃ + 8O₂ → 6CO₂ + 7H₂O + B₂O₃.
Explanation:
- For balancing a chemical equation, we should apply the law of conversation of mass. It states that the no. of atoms in the reactants side is equal to that of the products side.
So, the balanced equation:
<em>2C₃H₇BO₃ + 8O₂ → 6CO₂ + 7H₂O + B₂O₃.</em>
It is clear that 2.0 moles of C₃H₇BO₃ is completely burned in 8 m oles of oxygen and produce 6 moles of CO₂, 7 moles of H₂O and 1 mole of B₂O₃.
Answer:
C. The lowest-energy electron configuration of an atom has the maximum number of unpaired electrons, all of which have the same spin, in degenerate orbitals.
Explanation:
The Hund's rule is used to place the electrons in the orbitals is it states that:
1. Every orbital in a sublevel is singly occupied before any orbital is doubly occupied;
2. All of the electrons in singly occupied orbitals have the same spin.
So, the electrons first seek to fill the orbitals with the same energy (degenerate orbitals) before paring with electrons in a half-filled orbital. Orbitals doubly occupied have greater energy, so the lowest-energy electron configuration of an atom has the maximum number of unpaired electrons, and for the second statement, they have the same spin.
The other alternatives are correct, but they're not observed by the Hund's rule.
