Answer:
MnCO3 + 2H2O ⇄ MnO2 + HCO3- + 2e- +3H+
Explanation:
<u>The</u> unbalanced equation
MnCO3 ⇄ MnO2 + HCO3-
In MnCO3, the oxidation number of Mn is +2
In Mno2, the oxidation number of Mn is +4
The change from +2 to +4 requires an addition of 2 electrons (to the right side).
MnCO3 ⇄ MnO2 + HCO3- + 2e-
The total charge now is -3 on the right side. To balance this we add 3 hydrogen atoms on the right side.
MnCO3 ⇄ MnO2 + HCO3- + 2e- +3H+
On the right side we have 4 hydrogen atoms in total. On the left side we have 0 hydrogen atoms. So to balance, we have to add 2H2O on the left side
MnCO3 + 2H2O ⇄ MnO2 + HCO3- + 2e- +3H+
Now the reaction is balanced.
Answer:
67.4 % of C₉H₈O₄
Explanation:
To make titrations problems we know, that in the endpoint:
mmoles of acid = mmoles of base
mmoles = M . volume so:
mmoles of acid = 20.52 mL . 0.1121 M
mmoles of acid = mg of acid / PM (mg /mmoles)
Let's determine the PM of aspirin:
12.017 g/m . 9 + 1.00078 g/m . 8 + 15.9994 g/m . 4 = 180.1568 mg/mmol
mass (mg) = (20.52 mL . 0.1121 M) . 180.1568 mg/mmol
mass (mg) = 414.4 mg
We convert the mass to g → 414.4 mg . 1g / 1000mg = 0.4144 g
We determine the % → (0.4144 g / 0.615 g) . 100 = 67.4 %
