Answer:

Explanation:
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In this case, since 12.75 g of calcium iodide has the following number of moles (molar mass = 293.89 g/mol):

In such a way, since 1 mole of calcium iodide contains 2 moles of atoms of iodine, and one mole of atoms of iodine contains 6.022x10²³ atoms (Avogadro's number), we compute the resulting atoms as shown below:

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Hydrogen + oxygen --> water
2,1g + 16,8g = x
x = 18,9g
12000 I iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii
Hydrogen as it has only 1 proton and therefore only an atomic mass of 1...