Answer :
Final answer:
To determine the number of chlorine molecules in 35.5g of chlorine gas, calculate the number of moles by dividing the mass by the molar mass of Cl2 (70.92 g/mol), and then multiply that by Avogadro's number (6.022 × 10^23 molecules/mol).
Explanation:
To find out how many chlorine molecules are in 35.5g of chlorine gas, we need to use the molar mass of chlorine and Avogadro's number. The molar mass of chlorine (Cl2) is twice the average atomic mass of a chlorine atom because chlorine gas is diatomic (Cl2). The average atomic mass of chlorine is calculated using isotope abundances of chlorine-35 and chlorine-37. Using these isotopes, the average atomic mass is (0.7577 × 34.969 amu) + (0.2423 × 36.966 amu) = 35.46 amu. The molar mass is therefore 35.46 amu × 2 = 70.92 amu (g/mol).
Now, to calculate the number of moles in 35.5 grams of Cl2, we divide the mass by the molar mass:
Number of moles of Cl2 = 35.5 g / 70.92 g/mol
Using Avogadro's number (6.022 × 1023 molecules/mol), we can then find the number of molecules:
Number of Cl2 molecules = Number of moles of Cl2 × Avogadro's number.
since chlorine is one of the 7 diatomic elements we know that chlorine appears as Cl₂ gas naturally. That means that the molar mass of a chlorine gas is 70.9g/mol. That being said, first you need to find the number of moles of chlorine gas that are present in a 35.5g sample. To do this divide 35.5g by the molar mass of chlorine gas (70.9g/mol) to get 0.501mol of chlorine. Then you have to multiply 0.501mol by 6.02×10²³ to get the number of chlorine gas molecules. Therefore 3.01×10²³ molecules of chlorine gas are present in a 35.5g sample.
I hope that helps. Let me know in the comments if anything is unclear.
I hope that helps. Let me know in the comments if anything is unclear.
