Answer: 
formula units
Explanation:
According to avogadro's law, 1 mole of every substance occupies 22.4 L at STP and contains avogadro's number 
of particles.
To calculate the moles, we use the equation:
1 mole of 
contains of formula units
Thus 0.203 mole of contains =
of formula units
Answer:
Monatomic ions are made up of only one atom per ion, whereas polyatomic ions are made up of numerous atoms per ion.
Explanation:
C=0.184 mol/L
n=0.113 mol
n=CV
V=n/C
V=0.113/0.184=0.614 L = 614 mL
Answer:
98.8g (3 s.f.)
Explanation:
Use the mole = mass/mr equation to find the moles of CaO, then use the molar ratio to find the moles of Fe2O3, which is the same as CaO, (assuming the ratio is 1:1, as you haven't stated it clearly in the question). Then use the equation and input to find Mass, which is 98.8g to 3 s.f.
