<span>Prefixes are used in the metric system to indicate smaller or larger measurements</span>
Explanation:
Given that,
Mass of metal cube, m = 20 g
Volume of cube, V =5 mL
We need to find the density of the cube. Mass per unit volume equals density.

So, the density of the cube is 4 g/ml.
We know that the density of Aluminium is 4 g/mL.
So, the cube is not Aluminium cube.
Answer:
The molecular formula is C12H18O3
Explanation:
Step 1: Data given
The empirical formula is C4H6O
Molecular weight is 212 g/mol
atomic mass of C = 12 g/mol
atomic mass of H = 1 g/mol
atomic mass of O = 16 g/mol
Step 2: Calculate the molar mass of the empirical formula
Molar mass = 4* 12 + 6*1 +16
Molar mass = 70 g/mol
Step 3: Calculate the molecular formula
We have to multiply the empirical formula by n
n = the molecular weight of the empirical formula / the molecular weight of the molecular formula
n = 70 /212 ≈ 3
We have to multiply the empirical formula by 3
3*(C4H6O- = C12H18O3
The molecular formula is C12H18O3