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Water of crystallization

Problem

How many molecules of water of crystallization does one formula unit of start text, C, a, S, O, end text, start subscript, 4, end subscript in plaster of Paris have?
  • Your answer should be
  • an integer, like 6
  • a simplified proper fraction, like 3, slash, 5
  • a simplified improper fraction, like 7, slash, 4
  • a mixed number, like 1, space, 3, slash, 4
  • an exact decimal, like 0, point, 75
  • a multiple of pi, like 12, space, start text, p, i, end text or 2, slash, 3, space, start text, p, i, end text
start text, H, end text, start subscript, 2, end subscript, start text, O, end text
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