9. A lump of gold sample is suspected to have a mass of 500g and is found to have a relative den of 5.2

Question

Find what mass of gold is present in the sample
If the relative den of gold and aluminium are 19.3 and 2.6

Answer 1

g = gold mass
a = Al mass
p = gold volume
r = Al volume

g+a = 500 so a = 500 -g
500 / (p+r) = 5.2

g/p = 19.3 so p = g/19.3
a/r = 2.6 so r = a/2.6

500 / [ g/19.3 + a/2.6 ] = 5.2
500 / [ g/19.3 + (500-g)/2.6 ] = 5.2
solve for g

Answer 2

Good