What is the % Sn and % Cu in the sample?

Question

You are given a piece of metal alloy that is made of tin and copper. If the density of the sample is found to be 8.59 g/mL what is the % Sn and % Cu in the sample?

Answer 1

The element tin has three densities depending on various factors. Grey tin has a density of 5.77, ordinary tin has a density of 7.28, and white tin has a gravity of 7.365.

Copper has a density of 8.92.

 

Since the sample density is 8.59, it is clear that most of the sample is made of copper.

 

To answer this question, I will use the density of ordinary tin.

let x = the percentage of copper; then 1 - x = percentage of tin

then 8.92x + (1 - x)7.28 = 8.59

expanding, 8.92x + 7.28 - 7.28x = 8.59

combining, 1.34x = 1.31

x = 0.9776; times 100% = 97.76% copper

then 1 - x = 0.0224; times 100% = 2.24% tin