Answer: Lithium
Explanation: The balanced chemical equation is:
It can be seen, 4 moles of lithium combines with 1 mole of oxygen gas to produce 2 moles of lithium oxide.
Thus 8.4 moles of lithium combines with=of oxygen gas to produce 4.2 moles of lithium oxide.
As, Lithium limits the formation of product, it is the limiting reagent and Oxygen gas is present in excess, it is called the excess reagent. (4.6-2.1)=2.5 moles of oxygen gas are present in excess.
Answer:
93,32 % (w/w)
Explanation:
The Ca²⁺ of CaCO₃ was completely precipitate to CaC₂O₄ that results in H₂C₂O₄. The titration of this one is:
3H₂C₂O₄ + 2H⁺ + MnO₄⁻ → Mn²⁺ + 4H₂O + 6CO₂
As you required 35,62mL of 0,1092M MnO₄⁻, the moles of H₂C₂O₄ are:
0,03562L× =
3,890x10⁻³mol of MnO₄⁻× = <em>0,01167 mol of H₂C₂O₄</em>
The number of moles of CaCO₃ are the same number of moles of H₂C₂O₄ because every Ca²⁺ was converted in CaC₂O₄ that was converted in H₂C₂O₄. That means: <em>0,01167 mol of CaCO₃</em>
0,01167 mol of CaCO₃ are:
0,01167 mol of CaCO₃× = <em>1,168 g of CaCO₃</em>
As the mass of the initial mixture is 1,2516 g, the percentage by weight of CaCO₃ is:
×100 = <em>93,32 % (w/w)</em>
I hope it helps!