9. Which sample contains a mole of atoms?
A) 23 g Na
B) 24 g C
C) 42 g Kr
D) 78 g K

Sodium (Na) is the sample that contains a mole of atoms.

Given the following data:

Scientific data:

To determine the sample contains a mole of atoms:

Number of moles = 1.0 moles

Therefore, sodium (Na) is the sample that contains a mole of atoms.

Read more on number of moles here: link

option A. 23g Na

Explanation:

To know which of the options are correct, let's solve each of the options

A. Mass of Na = 23g

MM of Na = 23g/mol.

n = Mass /Molar Mass

n = 23/23 = 1mole

B. Mass of carbon = 24g

MM of carbon = 12g/mol

n = Mass /Molar Mass

n = 24/12 = 2mole

C. Mass of Kr = 42g

MM of Kr = 84g/mol

n = Mass /Molar Mass

n = 42/84 = 0.5mole

D. Mass of K = 78g

MM of K = 39g/mol

n = Mass /Molar Mass

n = 78/39 = 2mole.

From the above illustration, only 23g of Na contains a mole of the atom

catya that's not even a b or c