Which sample contains a total of 6.0 x 1023 molecules? select one: a. 4.0 g of he b. 14 g of li c. 80 g of br2 d. 4.0 g of h2

Option a. 4 g of He

Explanation:

6.02×10²³ is the Avogadro's number. The amount of units that corresponds to 1 mol, in this case the units are molecules.

Let's find out which mass corresponds to 1 mol (mass / molar mass)

a. 4g / 4g/mol = 1 mol He

b. 14g / 6.94 g/mol = 2.01 mol Li

c. 80g /159.8 g/mol = 0.5 moles Br₂

d. 4g / 2g/mol = 2 mol H₂

c-14 is carbon-14, or radiocarbon.   it is a radioactive isotope of carbon with an atomic nucleus containing 6 protons and 8 neutrons.

a corroding iron, if that's one of your choices