Question

A piece of gold jewelry weighs 11.54 g and has a volume of 0.675 cm3. The jewelry contains only gold (density = 19.3 g/cm3) and silver (density = 10.5 g/cm3). Assuming that the total volume of the jewelry is the sum of the volumes of the gold and silver that it contains, calculate the percentage of gold in the jewelry.

Answer 1

Answer:

Percentage of gold = 84.6%

Explanation:

Suppose the jewelry has x g of gold and y g of silver

The mass of both is the total mass of the jewelry then:

x + y = 11.54

And as the problem says the total volume is the sum of both volumes.

volume = mass / density

$\frac{x}{19.3} + \frac{y}{10.5} = 0.675$

Solving the system you get:

x = 9.764 g

y = 1.776 g

The percentage of gold in the jewelry is:

$X_{gold} = \frac{9.764}{11.54} * 100 = 84.6\%$