Determine the number of moles of O in 5.27 g Mg(OH)2, given the following molar masses:  (Mg: 24.31 g/mole; O: 16.00 g/mole; H: 1.01 g/mole).

Sure, here are the steps to determine the number of moles of O in 5.27 g Mg(OH)2:

1. First, calculate the molar mass of Mg(OH)2. The molar mass of Mg(OH)2 is the sum of the molar masses of its constituent elements, multiplied by the number of times each element appears in the compound.

   Molar mass of Mg(OH)2 = (24.31 g/mole for Mg) + 2 * (16.00 g/mole for O + 1.01 g/mole for H) = 24.31 g/mole + 2 * (17.01 g/mole) = 24.31 g/mole + 34.02 g/mole = 58.33 g/mole

2. Next, calculate the number of moles of Mg(OH)2 in the 5.27 g sample. The number of moles is the mass of the sample divided by the molar mass of the substance.

   Moles of Mg(OH)2 = 5.27 g / 58.33 g/mole = 0.090 moles

3. Finally, calculate the number of moles of O in the sample. Mg(OH)2 contains two moles of O for every mole of Mg(OH)2, so the number of moles of O is twice the number of moles of Mg(OH)2.

   Moles of O = 2 * 0.090 moles = 0.18 moles

So, there are 0.18 moles of O in the 5.27 g sample of Mg(OH)2.