<span>Actually, the heat of reaction hrxn s calculated by taking
the sum of the heats of formation of the products minus the sum of the heats of
formation of the reactants. However, at heat of formations of pure elements at
atmospheric conditions is zero, therefore the hf of N2 is not important since
it is zero anyway.</span>
Let us assume that the ring is a size 7 ring, which has a circumference of 54.3 millimeters. Converting this to centimeters, the circumference of the ring is:
54.3 mm = 5.43 cm
Now, we determine the number of gold atoms that will be present in this:
5.43 / 1 x 10⁻⁹
There will be 5.43 x 10⁹ atoms
We now determine the number of moles this is by:
one mole = 6.02 x 10²³ atoms
Moles = 5.43 x 10⁹ / 6.02 x 10²³
Moles = 9.01 x 10⁻¹⁵ moles
The molar mass of gold is 197 g/mol
The mass is 9.01 x 10⁻¹⁵ * 197
The mass of the strand is 1.76 x 10⁻¹² grams
Hey there!
When two or more substances combine, they create one or more new substances, which sometimes have different molecular structures from the original substances, meaning they absorb and radiate light in different ways, leading to a color change.
Hope this helps! :)
Answer:
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