When iron is added to HCl, 720 cm3 of hydrogen is produced. What is the mass of iron used? Fe(s) + 2HCl(aq) → FeCl2(aq) + H2 (g)

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hope that

so here we go

atomic mass

239 + 1 = y + 134 + 3 combine like terms

240 = y + 137             subtract 137 from both terms

240 - 137 = y

103 = y

atomic number

94 = z +54 + 0

94 = z + 54               subtract 54 from both sides.

40 = z

answer

the electron configuration that you gave me has 16 electrons ergo it has 16 protons ergo it is the element sulfur.