4. What is the total number of atoms in 3.0 molecules of propanone?

30

Explanation:

number of atom in ch3coch3 is

3 atom of c

6 atom of H

1 atom of o

total atoms = 10

in one molecule 10 atom are there

so in 3 molecule atoms will be 3×10=30

so total number of atom is 30 in 3 molecule of propanone

56 moles of   lieter in chemistry