A 20 L vessel contains 0.1 mole of $O_2$ at 300 K. $O_3$ is prepared in the vessel by subjecting $O_2$ to silent electric discharge till the volume is reduced to 15 L at 300K. What is the number of moles of $O_3$ formed?

A sample of hydrated copper sulfate (CuSO₄ ⋅ xH₂O) contains 0.25 moles of water. If the total mass of the hydrated salt is 62.5 g, and the anhydrous copper sulfate (CuSO₄) has a molar mass of 160 g/mol, what is the value of 'x' (the number of water molecules per formula unit)?

A 20 L vessel contains 0.1 mole of $O_2$ at 300 K. $O_3$ is prepared in the vessel by subjecting $O_2$ to silent electric discharge till the volume is reduced to 15 L at 300K. What is the number of moles of $O_3$ formed?