Question

A-potassiumB-leadC-ironD-magnesiumE-zinc​

Answer 1

The unknown substance : Lead

Further explanation

Given

Density of element

mass of unknown substance = 40 g

volume = 3.5 cm³

Required

The density of unknown substance

Solution

Density is the ratio of mass per unit volume  

The unit of density can be expressed in g/cm³ or kg/m³  

Density formula:  

$\large {\boxed {\bold {\rho ~ = ~ \frac {m} {V}}}}$

Input the value to find the density of an unknown substance :

ρ = 40 g : 3.5 cm³

ρ = 11.43 g/cm³

If we look at the table, the substance which has a density of 11.43 is Lead