Chlorine gas exists as diatomic molecules, Cl2. Natural chlorine consists of two stable isotopes, 35Cl and 37Cl, with molar masses 34.969gmol−1 and 36.966gmol−1, respectively. In a particular industrial process, chlorine gas enriched to 75.0%37Cl (by atom) is required.
A reaction vessel is charged with exactly 3.00×1024 molecules of this enriched Cl2. Avogadro’s constant is 6.022×1023mol−1.
(a) Calculate the average molar mass of one mole of the enriched Cl2 molecules.
(b) Determine the mass, in grams, of the 3.00×1024 Cl2 molecules placed in the vessel.
(c) Convert the mass from part (b) to kilograms and express the result to three significant figures.
(d) If the enrichment were instead the natural abundance (24.23%37Cl by atom), would the mass corresponding to the same particle count increase, decrease, or remain the same? Justify your answer qualitatively in one or two sentences based on atomic masses.