Question

which of the ff samples contains 6 moles of atoms?
a. 2 moles of CS2
b. 3 moles of HF
c. 6 moles of O2
d. more than one response

Answer 1

To find the number of atoms in a molecule: Add the numbers in the subscripts for each element ( remember, no subscript means 1) [ subscript = what is written below the line of the element symbols ]

a. CS₂ . Here, the subscript for C = 1, S = 2. So, number of atoms = 1 + 2 = 3. Thus, there are 3 atoms/molecule of CS₂.

2 moles of CS₂ is taken. So, number of moles of atoms = Number of moles of molecule x atoms /molecule. = 2 moles of CS₂ x 3 atoms /molecule = 6 moles of atoms

Similarly:

b. HF : number of atoms = 1 + 1 = 2 ( subscript of H =1 , subscript of F = 1).

So, moles of atoms = 3 moles x 2 atoms = 6 moles of atoms

c. O₂ . Number of atoms =2 ( subscript of O = 2)

So,moles of atoms = 6 moles x 2 atoms = 12 moles of atoms.

Hence, both a and b have 6 moles of atoms. So, the answer is (d)