The answer is 69.048%.
Mass of potassium dichromate (K₂Cr₂O₇) is 294 g, which is a 100%.
Given mass of chromium is 52 g. So, the mass percent of chromium in the compound is 17.687%:
52 g : x% = 294 g : 100%
x = 52 ÷ 294 × 100 %
x = 17.687%
Given mass of potassium is 39 g. <span>So, the mass percent of potassium in the compound is 13.265%:
39 g : x% = 294 g : 100%
x = </span>39 ÷ <span>294 × 100 %
x = 13.265%
Therefore, </span>the mass percent of oxygen in the compound is <span>69.048%:
100% - </span>17.687% - <span>13.265% = 69.048%.</span>
The reactants of the reaction of single replacement that produces ZnCl₂ and H₂ is Zn + 2HCl
Explanation
In a single replacement reaction is a chemical reaction whereby an element react with compound and take the place of another element in that compound.
zn displaces H from HCl to form ZnCl₂ and H₂ according to below equation.
Zn +2HCl → ZnCl₂ + H₂
