The correct answer among the choices given is the first option.The teacher most likely is talking about distillation of a mixture. Distillation is a unit operation that separates component substances from a liquid mixture which is shown by the teacher. Also, the most common purifying technique in the production of gasoline is by this process.
I mol of anything is 6.02 * 10^23 (in this case molecules of water)
6 mols of water = x
1/6 = 6.02 * 10^23 / x Cross multiply
x = 6 * 6.02* 10^23
x = 3.612 * 10^24 molecules in 6 mols of water
C: Z because it is the only area of land that is darkened.
Answer: 2755.2 g of 
will be produced from 24.6 mol of haematite.
Explanation:
The balanced chemical equation is:
According to stoichiometry :
1 mole of 
produce = 2 moles of
Thus 24.6 moles of will produce=
of
Mass of 
Thus 2755.2 g of will be produced from 24.6 mol of haematite.
