Question

An 18-karat gold necklace is 75% gold by mass, 16% silver, and 9.0% copper.

If 18-karat gold has a density of 15.5 , what is the volume in cubic centimeters?

Answer 1

Let the total mass of the alloy considered be 1kg= 1000 g

So, 75%mass given by gold has volume : 750 / (19.3) = 38.8601 cm^3

Silver volume = 160/10.5 = 15.2381cm^3

Copper volume = 90/8.90 = 10.1124 cm^3

So, total volume = 64.2106 cm^3

Now total density = mass/volume = 1000g/totalvolume = 15.574 = 15.6 g/cm^3

Answer 2

Just so you know, the term "karat" refers to purity, and in this case 18 (out of a max of 24) karat gold gives you a purity of 75% (as shown in thisproblem) of gold present in the alloy. In order to find the volume, you would need to have another given value (likely in grams or kilograms) to representthe weight of the object you were trying to find the volume for.
With the weight (call it x), you would just divide X grams by density to find the volume in cubic centimeters.
Example: Mass of gold = X
Density = 15.5 g/cm^3
X= 20 g
(20g)/(15.5g/cm^3)=
Volume = 1.29 cm^3

Answer 3

36.5cm^3

Answer 4

0.232 cc

Answer 5

3.2 cm^3