How many gold atoms are in an 0.375 ounce, 18 k gold bracelet? (18 k gold is 75% gold by mass.) ?

Question

Lea Garrett

Chemistry

13 June, 00:01

How many gold atoms are in an 0.375 ounce, 18 k gold bracelet? (18 k gold is 75% gold by mass.) ?

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Answers (1)

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Talan Dyer · Answer 1

Answer is: 2,42·10²² atoms of gold.

1 ounce (oz) is equal to 28,34952 grams (g).

0,375 oz = 10,631 g.

75% gold = 10,631 g · 0,75 = 7,973 g.

n (Au) = m (Au) : M (Au).

n (Au) = 7,973 g : 197 g/mol.

n (Au) = 0,0404 mol.

N (Au) = n (Au) · Na.

N (Au) = 0,0404 mol · 6,023·10²³ 1/mol.

N (Au) = 2,42·10²².

n - amount of substance.

Na - Avogadro number.