Molality of the solution is defined as the number of moles of a substance dissolved divided by the mass of the solvent:
Molality = number of moles / solvent mass
From the concentration of 39% (by mass) of HCl in water, we construct the following reasoning:
in 100 g solution we have 39 g hydrochloric acid (HCl)
number of moles = mass / molecular weight
number of moles of HCl = 39 / 36.5 = 1.07 moles
solvent (water) mass = solution mass - hydrochloric acid mass
solvent (water) mass = 100 - 39 = 61 g
Now we can determine the molality:
molality = 1.07 moles / 61 g = 0.018
Answer : The volume of oxygen at STP is 112.0665 L
Solution : Given,
The number of moles of
= 5 moles
At STP, the temperature is 273 K and pressure is 1 atm.
Using ideal gas law equation :

where,
P = pressure of gas
V = volume of gas
n = the number of moles
T = temperature of gas
R = gas constant = 0.0821 L atm/mole K (Given)
By rearranging the above ideal gas law equation, we get

Now put all the given values in this expression, we get the value of volume.

Therefore, the volume of oxygen at STP is 112.0665 L
Answer:
I hope this is it. I'm not really sure.