Question

1.) Calculate the number of molecules in 7.00 moles H2S.

Express your answer numerically in molecules.

2.) Calculate the number of moles of Cl atoms in 3.61×10²⁴ formula units of magnesium chloride, MgCl2.

Express your answer numerically in moles.

Answer 1

1. We know that 1 mole of any substance contains Avogadro's Number of molecules. So, 1 mole of H2S contains Avogadro's number (6.022 x 1023) molecules. 7.00 moles of H2S would contain 7.00 mol * 6.022 × 1023 molecules/mol 4.2154 x 1024 molecules of H2S Number of molecules of H2S = 4.21 x 1024 molecules 2. We know that 1 mole of any substance contains Avogadro's Number of molecules. 1 mole of MgCl2 contains Avogadro's number (6.022 x 1023) MgCl2 molecules. 3.61x1024 molecules of MgCI2 would have 3.61x1024/ 6.022 x 1023 moles of MgCI2 Number of moles of MgCI2 3.61x1024/ 6.022 x 1023 5.994686 mol We know that 1 mole of MgCI2 produces 2 moles of C-ions. So 5.994686 mol of MgCI2 would produce 2* 5.99468611.98937 mol of C- ions 12.0 mol Number of moles of chloride ions (Cl-) = 12.0 mol