Respuesta :
Answer:
The empirical formula is = [tex]C_3H_2Cl[/tex]
Explanation:
Mass of water obtained = 0.0617 g
Molar mass of water = 18 g/mol
Moles of [tex]H_2O[/tex] = 0.0617 g /18 g/mol = 0.003428 moles
2 moles of hydrogen atoms are present in 1 mole of water. So,
Moles of H = 2 x 0.003428 = 0.006856 moles
Molar mass of H atom = 1.008 g/mol
Mass of H in molecule = 0.006856 x 1.008 = 0.006911 g
Mass of carbon dioxide obtained = 0.451 g
Molar mass of carbon dioxide = 44.01 g/mol
Moles of [tex]CO_2[/tex] = 0.451 g /44.01 g/mol = 0.01025 moles
1 mole of carbon atoms are present in 1 mole of carbon dioxide. So,
Moles of C = 0.01025 moles
Molar mass of C atom = 12.0107 g/mol
Mass of C in molecule = 0.01025 x 12.0107 = 0.12311 g
Given that the dry-cleaning solvent only contains hydrogen, chlorine and carbon. So,
Mass of Cl in the sample = Total mass - Mass of C - Mass of H
Mass of the sample = 0.25 g
Mass of Cl in sample = 0.25 - 0.12311 - 0.006911 = 0.119979 g
Molar mass of Cl = 35.453 g/mol
Moles of Cl = 0.119979 / 35.453 = 0.003384 moles
Taking the simplest ratio for H, Cl and C as:
0.006856 : 0.003384 : 0.01025
= 2 : 1 : 3
The empirical formula is = [tex]C_3H_2Cl[/tex]
