Answer:
M is cobalt (Co)
Explanation:
Step 1: Data given
Mass of MCl2(H2O)6 = 2.9237 grams
After completely drying the sample (which means removing the 6 moles of H2O per mole of MCl2), the sample weighs 1.5941 g.
Step 2: Calculate mass of water
Mass of water = 2.9237 - 1.5941 = 1.3296 grams
Step 3: Calculate moles water
Moles water = mass water / molar mass water
Moles water = 1.3296 grams / 18.02 g/mol
Moles water = 0.07378 moles
Step 4: Calculate moles of the whole substance
For 1 mol MCl2(H2O)6 we have 6 moles H2O
Number of moles of the whole substance = 0.07378 / 6 = 0.01230 moles
Step 5: Calculate molar weight of the substance
Molar weight = mass / moles
Molar weight = 1.5941 grams / 0.01230 moles
Molar weight = 129.6 g/mol
Step 6: Calculate molar weight of M
Molecular weight of M = 129.6 - (2*35.45)
Molecular weight of M = 58.7 g/mol
M is cobalt (Co)
