How many moles are in 3.4 grams of silicone dioxide, sio2

number of moles in 3.4 grams of SiO2 = 0.06 moles

Explanation:

SiO2 compound is the combination of silicon and Oxygen molecules. Silicon dioxide contains only 1 mole according to the question. The molecular mass of the compound is the sum of the atomic mass of each atom of element present in the compound.

This means 1 mole of silicon dioxide = molecular mass of silicon dioxide

molecular mass of Si02 = 28.0855 + 15.999(2) = 60.0835 g

If 1 mole of SiO2 = 60.0835 g

   ? mole        =   3.4 g

cross multiply

number of mole in 3.4 g = 3.4/60.0835 = 0.05658791515

 = 0.06 moles

number of moles in 3.4 grams of SiO2 = 0.06 moles

your answer is a. the enthalpy of formation for a pure element in its standard state is always positive.

it is stable as it is in group 0 which have full outer shells of electrons