Question

A certain metal oxide has the formula MO where M denotes the metal. A 61.16−g sample of the compound is strongly heated in an atmosphere of hydrogen to remove oxygen as water molecules. At the end, 53.54 g of the metal is left over. If O has an atomic mass of 16.00 amu, calculate the atomic mass of M and identify the element

Answer 1

the metal is Cadmium (Cd), the oxide is Cadmium oxide (CdO)

Step-by-step explanation:

Step 1: The equation

mMO ⇔ mM + mO

Step 2: calculating mass

Given is the mass of the metaloxide (61.16g) and the mass of the metal, since the oxygen was removed (53.54g)

The mass of the oxide can be calculate by:

mO = mMO - mM

mO = 61.16 - 53.54 = 7.62g

Step 3: Calculating moles oxide

mole = mass/ molar mass

mole = 7.62g / 16g/mole = 0.47625 mole

Step 4: moles metal

For 1 mole O2 we will have 1 mole metal

so we have 0.47625 moles of metal

Step 5: Calculating molar mass of metal

Molar mass = mass / moles

Molar mass = 53.54g / 0.47625 mole

Molar mass = 112.41 g/mole

If we look at the periodic table ⇒ Cadmium has a molar mas of 112.41 g/mole

So the metal is Cadmium (Cd), the oxide is Cadmium oxide (CdO)