It is often possible to change a hydrate into an anhydrous compound by heating it to drive off the water (dehydration). A 43.19 gram sample of a hydrate of MgBr2 was heated thoroughly in a porcelain crucible, until its weight remained constant. After heating, 27.21 grams of the anhydrous compound remained. What is the formula of the hydrate?

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Explanation:

Let denote the number of formula units for every formula unit. The formula of the hydrate would be .

Look up the relative atomic mass of each element on a modern periodic table:

Formula mass:

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The anhydrous compound would be . There was of this compound. Calculate the number of moles of formula units in that much of this compound:

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During heating, of water escaped from the hydrate. Calculate the number of formula units in that of :

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In other words, approximately of formula units (and hence the same number of moles of formula units) contain approximately of formula units. Calculate the ratio between the two:

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Hence, the formula of the hydrate would be .

it is a good conductor

explanation:

the correct answer would be b. amelia, because the particals of gas move really fast (charged particals) and gas also has a lot of room (particals move independently) so the only answer that has both of those is amelia's.