What important result did Becquerel observe when he placed the uranium salt crystals and unexposed photographic film in a drawer
2 answers:
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The answer should be <span>balance electrically
</span><span>Chemical reactions that form ions should have a balanced charge. The example of the reaction is HCl. When forming ions, the equation should be:
HCl => </span>
+ 
In this case, the hydrogen has one plus charge and chlorine has one negative charge. The resultant should be zero, so it's balanced.
</span><span>Chemical reactions that form ions should have a balanced charge. The example of the reaction is HCl. When forming ions, the equation should be:
HCl => </span>
In this case, the hydrogen has one plus charge and chlorine has one negative charge. The resultant should be zero, so it's balanced.
Answer:
<u>5 moles S x (36.02 g S/mole S) = 180.1 grams of S</u>
Explanation:
The periodic table has mass units for every element that can be correlated with the number of atoms of that element. The relationship is known as Avogadro's Number. This number, 6.02x , is nicknamed the mole, which scientists found to be a lot more catchy, and easier to write than 6.02x
. <u>The mole is correlated to the atomic mass of that element.</u> The atomic mass of sulfur, S, is 36.02 AMU, atomic mass units. <u>But it can also be read as 36.02 grams/mole.</u>
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<u>This means that 36.02 grams of S contains 1 mole (6.02x</u><u>) of S atoms</u>.
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This relationship holds for all the elements. Zinc, Zn, has an atomic mass of 65.38 AMU, so it has a "molar mass" of 65.38 grams/mole. ^5.38 grams of Zn contains 1 mole of Zn atoms.
And so on.
5.0 moles of Sulfur would therefore contain:
(5.0 moles S)*(36.02 grams/mole S) = <u>180.1 grams of S</u>
Note how the units cancel to leaves just grams. The units are extremely helpful in mole calculations to insure the correct mathematical operation is done. To find the number of moles in 70 g of S, for example, we would write:
(70g S)/(36.02 grams S/mole S) = 1.94 moles of S. [<u>Note how the units cancel to leave just moles</u>]