Explanation:
Let us assume that the given data is as follows.
V = 3.10 L, T = 
= (19 + 273)K = 292 K
P = 40 torr (1 atm = 760 torr)
So, P = 
= 0.053 atm
n = ?
According to the ideal gas equation, PV = nRT.
Putting the given values into the above equation to calculate the value of n as follows.
PV = nRT
0.1643 = 
n = 
It is known that molar mass of ethanol is 46 g/mol. Hence, calculate its mass as follows.
No. of moles = 
mass = 
g
= 0.315 g
Thus, we can conclude that the mass of liquid ethanol is 0.315 g.
in order to determine empirical formula we have to determine the mole ratio of the given elements
Let the total mass of the compound is 100g
as given that the compound has 40% sulfur , so mass of sulfur = 40g
as given that the compound has 60% oxygen, so mass of oxygen = 60g
let us calculate the moles of each element
Moles of sulfur = mass / atomic mass = 40 / 32 = 1.25
moles of oxygen = mass / atomic mass = 60/ 16 = 3.75
In order to get simple ratio of moles we will divide both the moles with least number of moles which is 1.25
moles of sulfur = 1.25 / 1.25 = 1
moles of oxygen = 3.75 /1.25 = 3
So empirical formula will be SO₃
Structure along with ¹H-NMR is shown below.
Signal for Hₐ; Based on multiplicity of of the peak, a
Singlet peak (the only singlet peak present in spectrum) at
2.2 ppm was assigned to Hₐ. As the methyl group in not coupling with any other proton so it gave a singlet peak.
Signal for Hb; Based on multiplicity of of the peak, a
Quartet peak (the only quartet peak present in spectrum) at
2.4 ppm was assigned to Hb. As the methylene group in coupling with methyl group having three protons so it gave a Quartet peak.
Signal for Hc; Based on multiplicity of of the peak, a
Triplet peak (the only triplet peak present in spectrum) at
1.1 ppm was assigned to Hc. As the methyle group in coupling with methylene group having two protons so it gave a Triplet peak.
