6. Chemical Quantities & Aqueous Reactions
Balancing Redox Reactions: Acidic Solutions
1PRACTICE PROBLEM
A 0.350 g sample of a certain semimetal M heated in air yielded the matching oxide M2O3. The reaction needed 7.67 mL of 0.125 M Cr2O72− when the oxide was dissolved in aqueous acid and titrated with K2Cr2O7. The unbalanced equation for the titration is H3MO3(aq) + Cr2O72−(aq) → H3MO4(aq) + Cr3+(aq) (in acid).
How many moles of semimetal were present in the initial 0.350 g sample and how many moles of oxide were formed?
A 0.350 g sample of a certain semimetal M heated in air yielded the matching oxide M2O3. The reaction needed 7.67 mL of 0.125 M Cr2O72− when the oxide was dissolved in aqueous acid and titrated with K2Cr2O7. The unbalanced equation for the titration is H3MO3(aq) + Cr2O72−(aq) → H3MO4(aq) + Cr3+(aq) (in acid).
How many moles of semimetal were present in the initial 0.350 g sample and how many moles of oxide were formed?