Why can the same earthquake have different ratings on the 2 scales.
1 answer:
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Answer:
The value of x is 7.
Explanation:
When a hydrated salt is heated, the water evaporates because it has a lower boiling point (373 K) and what remains is the <em>anhydrous salt</em> (without water) The mass of the hydrated salt is equal to the sum of the anhydrous salt and the water. Since we have 2 of these 3 data, we can look for the mass of water.
mass of FeSO₄.xH₂O = mass of FeSO₄ + mass of H₂O
mass of H₂O = mass of FeSO₄.xH₂O - mass of FeSO₄
mass of H₂O = 1.983g - 1.084g = 0.899g
This means that 0.899g of water accompany 1.084 g of the salt. We want to know how many grams of water accompany 1 mol of the salt (in the molecular formula we have 1 mol of FeSO₄). Since the molar mass of is 152g/mol, we can establish:
As a result 1 mol of FeSO₄ is accompanied by 126 g of water. If we pass that mass into moles:
Finally, the number of moles of water in the molecular formula is x = 7.