2.5 moles O2
Determine the mass (grams)

80g

Explanation:

Given parameters:

Number of moles of O₂  = 2.5moles

Unknown:

Mass of O₂  = ?

Solution:

To solve this problem, we use the expression below

      Mass  = number of moles x molar mass

Molar mass of O₂  = 2(16) = 32g/mol

  So;

   Mass  = 2.5 x  32 = 80g

radioactive decay occurs in unstable atomic nuclei – that is, ones that don't have enough binding energy to hold

the nucleus together due to an excess of either protons or neutrons.

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