Questions: Calculate the number of moles of magnesium oxide, MgO in 68.05 g of the compound.

Solution Steps

To find the number of moles, we first need to determine the molar mass of magnesium oxide (MgO). The molar mass is the sum of the atomic masses of magnesium (Mg) and oxygen (O).

• Atomic mass of Mg: 24.3050 g/mol
• Atomic mass of O: 15.9994 g/mol

\[ \text{Molar mass of MgO} = 24.3050 \, \text{g/mol} + 15.9994 \, \text{g/mol} = 40.3044 \, \text{g/mol} \]

Next, we use the formula to calculate the number of moles:

\[ \text{Number of moles} = \frac{\text{Mass}}{\text{Molar mass}} \]

Given the mass of MgO is 68.05 g:

\[ \text{Number of moles} = \frac{68.05 \, \text{g}}{40.3044 \, \text{g/mol}} = 1.688 \, \text{moles} \]

Final Answer