Answer:
0.119 moles
Explanation:
molar mass of Fe = 55.845g
to find moles = mass/ molar mass
so moles of Fe = 20/55.845
= 0.358 moles
for the equation you are given
for every three Fe, it produces 1 Fe3O4 , meaning the ratio is 3:1
if you have 0.358 moles of Fe, that means the number of moles of Fe3O4 will equal to one third of that,
thus
moles of Fe3O4 = 1/3 x 0.358 = 0.119
It seems that nitrogen is, but its odd tbh.
Molality of C2H5OH is 1.1.27m.
What is Molality?
Molality is no.of moles present in One Kg solution .
Molality is represented by m
m= no.of moles/ weigt of solution in kg
Given is Molarity= 51.30M
molar mass of C2H5OH is 46g / mol , Density =0.9349g/ ml
Density=m/V
V = 107 ml
Molarity= no of moles/ Volume
51.5×46×107= x × 1000
weight of C2H5OH = 27.7g
molality = 27.7/1000××46
m= 1.27m
to learn more about Molality click brainly.com/question/20380670
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<h3>
Answer:</h3>
250.756 moles He
<h3>
Explanation:</h3>
From the question we are given;
Volume, L = 685 L
Temperature, T = 621 K
Pressure, P = 189 × 10 kPa
We are required to calculate the number of moles of the gas,
Using the Ideal gas equation,
PV = nRT, where P is the pressure, V is the volume, T is the temperature, n is the number of moles, and R is the ideal gas constant.
We can replace the known variables and constant in the equation to get the unknown variable, n.
Using ideal gas constant as 8.3145 L.kPa/K/mol



n = 250.756 moles
The moles of helium contained in the sphere is 250.756 moles