In order to <span>complete and balance the following reactions, you should add a Fe into it. So it will look like uo2+ +cr o^2- 7 ـــــــــــــــــــــ uo2+ +cr3+Fe. The answer to the following given statement or missing answer is Fe. </span>
17) 8.4 / 20 x 100
18) 20 . 0.5150
19) 6,50% because (as you said) the law of definite proportions states that regardless of the amount, a compound is always composed of the same elements in the same proportion by mass
Multiply this number by avogadro's number- 6.02 times 10^23