Answer :
Answer:
The calculated mass of one atom of oxygen-18 is approximately 2.99×10⁻²³ grams
Explanation:
The given mass of an oxygen-18 atom = 18.0042 amu
The definition of the atomic mass unit is the mass equivalent to the mass of one twelfth the atomic mass of one atom of carbon-12. The atomic mass unit is used to express the mass of an isotope of an element
1 amu = 1.66 × 10⁻²⁴ grams
Therefore;
18.0042 amu = 18.0042 × 1.66 × 10⁻²⁴ grams ≈ 2.99×10⁻²³ grams
The calculated mass of one atom of oxygen-18 ≈ 2.99×10⁻²³ grams
The atomic mass unit can be taken as the mass in grams of one mole of the substance
Therefore, the mass of one mole of the oxygen 18 atom = 18.0042 g