Determine what percentage of the chain is gold, by mass, to at least 1 decimal place?

Question

In the video, the water level was 15 milliliters before adding the chain, and 20 milliliters after adding the chain. When I weighed the chain, its mass was 73.9 grams.

I believe the chain is solid metal (not gold plated), but is probably a blend of gold and other metals. I looked up that gold has a density of 19.3 g/ml, while the other metals like silver and copper usually blended with gold have a combined density of about 9.7 g/ml.

Determine what percentage of the chain is gold, by mass, to at least 1 decimal place?

Answer 1

volume of chain = 20 - 15 = 5ml

 

Let mass of gold in the chain = G

Let mass of blended material = B

 

G/19.3  + B/9.7 = 5

 

mas of chain = 73.9

 

G + B = 73.9

 

Solve this simultaneous equation

 

you will get G = 51.06g

 

%age gold = 51.06/73.9 = 69.1%

:)