It is known that 40% by mass of compound XY3 is substance X. While XY3 was formed from X and Y, all 24 grams of Y substance were used, and 16 grams increased from X. What is the mass of the initial substance X in grams?
16
24
32
40
64
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#7 how does the structure of amino acids allow them to form a polypeptide? each amino acid has an amino group and a carboxyl group. each amino acid has a hydrogen atom and a carboxyl group. each amino acid has a carboxyl group and an r group. each amino acid has an r group and a hydrogen atom.