This question is asking for the thickness of a piece of lead. This question is going to use the volume of the lead as well as the density to solve for the thickness. We are told the piece of lead is a square. We can write a formula for the volume.
V = l · w · d
We know the length and width are 2.5 inches since it is a square. We are asked for the thickness in mm, but we will use cm as this will relate better to the density.
2.5 inches x 2.54 cm/1in = 6.35 cm
V = (6.35)(6.35)d
V = (40.3225)d
The mass of the piece of lead is 525 mg, which is equal to 0.525 g. We can solve for the volume using the density and the mass.
density = mass/volume
volume = mass/density
V = 0.525 g / 11.342 g/cm³
V = 0.0463 cm³
V = 0.0463 cm³ = 40.3225d
d = (0.0463/40.3225)
d = 0.00115 cm = thickness
0.00115 cm x 10 mm/cm
thickness = 0.0115 mm
The thickness of the square sheet of lead is 0.0115 mm.
