How many atoms of 0xygen are there in 8.43 g of KMnO4?

Question

Could someone please explain this?

Answer 1

moles KMnO4 in 8.43 g = 8.43/molar mass KMnO4. Then molecules KMnO4 will be moles x 6.022 x 10^23 molecules/mole and that times 4 will give you atoms oxygen.