Question

An alloy is made by mixing 540 g of copper of density 9 g cm^-3 with 240 g of iron of density 8 g cm^-3. Find the density of the alloy assuming that the volume of each metal does not change during mixing.

Answer 1

Mass of copper = 540 g
Density of copper = 9 g/cm³
Volume of copper used in the alloy = mass of copper / density
= 540/9 = 60 cm³
Mass of iron = 240 g
Density of iron = 8 g/cm³
Volume of iron used in the alloy = mass of iron / density
= 240/8 = 30 cm³
Total mass of the alloy = 540 + 240 = 780 g
Total volume of the alloy = 60 + 30 = 90
Density of the alloy = mass of the alloy / density of the alloy = 780 / 90 = 8.67 g/cm³