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 75.9 grams.

Question

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

water level was 15 ml

after the chain, it's 20 ml

the chain displaced 5 ml

the chain weighs 75.9 g

75.9 grams per 5 ml is 75.9/5 = density of 15.18 g/ml

the density of gold is 19.3 g/ml

15.18/19.3 = 78.65% gold