The answer I got was : 52.2
The mass of iron (III) oxide (Fe2O3) : 85.12 g
<h3>Further explanation</h3>
Given
3.20x10²³ formula units
Required
The mass
Solution
1 mole = 6.02.10²³ particles
Can be formulated :
N = n x No
N = number of particles
n = mol
No = 6.02.10²³ = Avogadro's number
mol of Fe₂O₃ :

mass of Fe₂O₃ (MW=160 g/mol)

☀️
Molar mass of 


<u>As we know</u>–
1 mol =
formula units
1 mol
= 143.092 g =
formula units
Henceforth –
formula units
–



Answer: 0.20 M
Explanation:
According to the dilution law,

where,
= molarity of stock solution = 1.40 M
= volume of stock solution = 72.0 ml
= molarity of diluted solution = m
= volume of diluted solution = 248 ml


Now 124 mL portion of this prepared solution is diluted by adding 133 mL of water.
According to the dilution law,

where,
= molarity of stock solution = 0.41 M
= volume of stock solution = 124 ml
= molarity of diluted solution = m
= volume of diluted solution = (124 +133) ml = 257 ml


Thus the final concentration of the solution is 0.20 M.
Answer: The concentration of unknown sample is 1.8 mg/ml
Explanation:
According to the dilution law,
where,
= concentration of stock solution = ?
= volume of stock solution = 0.25 ml
= concentration of diluted solution = 0.45 mg/ml
= volume of diluted solution = (0.25+0.75) ml = 1.00 ml
Putting in the values we get:
Therefore, concentration of unknown sample is 1.8 mg/ml