Answer
a) Au, Ag, Cu
b) 1337 K
c) No, it's osmium.
d) 4.185 g
e) 688,800 g; $35.88 million
Work Step by Step
a) According to the text, 18- carat gold is made of gold (Au - sixth period), silver ( Ag - fifth period) and copper (Cu - fourth period, ALL three from group 11).
b) $T(K) = T(°C) +273$ by definition
For $T(°C)= 1064°C$:
$T(K)=1337 K$
c) The most dense element is Osmium (Os) with 22.59 g/cm$^3$.
d) Since 18-carat means 75% of pure gold:
$5.58g \times 0.75= 4.185 g$
e) Each ring loses 6.15 mg of gold per year, each couple has two rings and in the US there are 56 million couples; thus, the total gold loss is:
$6.15\ mg \times \dfrac{1\ g}{1000\ mg}\times2\times 56,000,000 = 688,800\ g$
Since gold costs $\$$1620 per troy ounce and one troy ounce equals 31.1 g, the total value loss:
$688,800\ g\times \dfrac{1\ t.o.}{31.1\ g} \times \dfrac{\$ 1620}{1\ t.o.}= \$35.88\ million$
