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One litre flask containing vapours of methyl alcohol (Mol mass 32 ) at a pressure of 1 atm and 25 degree Celsius was evacuated till the final pressure was 10^(-3)mm. How many molecules of methyl alcohol were left in the flask. Ans: 3.24 × 10^16 molecules Can you explain this answer?
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One litre flask containing vapours of methyl alcohol (Mol mass 32 ) at...
The final pressure after evacuation is given in mm Hg and hence has to be converted to atm.
 760 mm Hg = 1 atm
thus 0.001 mm Hg = 1. 31  x  10^-6 atm.
As we know that at STP conditions 1 Mole of a substance occupies 22.4 L of volume and contains 6.022  x  10^23 molecules
Here the volume occupied at STP = 1 Litre.
Thus no. of moles = 1/22.4 = 0.044 Moles of methanol and no. of molecules = 0.044 x  (6.0^22 x 10^23) = 2.68  x 10^22
Hence, at 1.31  x  10^-6 atm pressure, no. of molecules will be
= (2.68 x 10^22 )  x  (1.31  x  10^-6)
Thus no. of molecules = 3.51  x 10^16
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One litre flask containing vapours of methyl alcohol (Mol mass 32 ) at...
Given Information:

- Volume of the flask = 1 liter = 1000 cm³
- Pressure of the vapors = 1 atm
- Temperature of the vapors = 25°C = 298 K
- Final pressure after evacuation = 10^(-3) mm

Conversion of Pressure:

To solve this problem, we need to convert the final pressure from millimeters (mm) to atmospheres (atm).
1 mm = 0.00133 atm
So, the final pressure is 10^(-3) mm = 10^(-3) * 0.00133 atm = 1.33 * 10^(-6) atm.

Calculating the Number of Molecules:

To calculate the number of molecules, we can use the ideal gas equation: PV = nRT.

- P = Pressure in atm (1 atm initially and 1.33 * 10^(-6) atm finally)
- V = Volume in liters (1 liter initially)
- n = Number of molecules in moles
- R = Gas constant = 0.0821 L·atm/(mol·K)
- T = Temperature in Kelvin (298 K)

We can rewrite the equation as:
n₁ = (P₁ * V₁) / (R * T) (initial number of molecules)
n₂ = (P₂ * V₁) / (R * T) (final number of molecules)

Substituting the values:
n₁ = (1 atm * 1 liter) / (0.0821 L·atm/(mol·K) * 298 K)
n₂ = (1.33 * 10^(-6) atm * 1 liter) / (0.0821 L·atm/(mol·K) * 298 K)

Simplifying the equations:
n₁ = 0.0406 moles
n₂ = 5.36 * 10^(-11) moles

Converting Moles to Molecules:

To convert moles to molecules, we use Avogadro's number, which is 6.022 x 10^23 molecules per mole.

Number of molecules = Number of moles * Avogadro's number

Substituting the values:
Number of molecules initially = 0.0406 moles * 6.022 x 10^23 molecules/mole
Number of molecules finally = 5.36 * 10^(-11) moles * 6.022 x 10^23 molecules/mole

Simplifying the equations:
Number of molecules initially = 2.45 x 10^22 molecules
Number of molecules finally = 3.24 x 10^16 molecules

Conclusion:

Therefore, the number of molecules of methyl alcohol left in the flask after evacuation is approximately 3.24 x 10^16 molecules.
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One litre flask containing vapours of methyl alcohol (Mol mass 32 ) at a pressure of 1 atm and 25 degree Celsius was evacuated till the final pressure was 10^(-3)mm. How many molecules of methyl alcohol were left in the flask. Ans: 3.24 × 10^16 molecules Can you explain this answer?
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One litre flask containing vapours of methyl alcohol (Mol mass 32 ) at a pressure of 1 atm and 25 degree Celsius was evacuated till the final pressure was 10^(-3)mm. How many molecules of methyl alcohol were left in the flask. Ans: 3.24 × 10^16 molecules Can you explain this answer? for Class 11 2024 is part of Class 11 preparation. The Question and answers have been prepared according to the Class 11 exam syllabus. Information about One litre flask containing vapours of methyl alcohol (Mol mass 32 ) at a pressure of 1 atm and 25 degree Celsius was evacuated till the final pressure was 10^(-3)mm. How many molecules of methyl alcohol were left in the flask. Ans: 3.24 × 10^16 molecules Can you explain this answer? covers all topics & solutions for Class 11 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for One litre flask containing vapours of methyl alcohol (Mol mass 32 ) at a pressure of 1 atm and 25 degree Celsius was evacuated till the final pressure was 10^(-3)mm. How many molecules of methyl alcohol were left in the flask. Ans: 3.24 × 10^16 molecules Can you explain this answer?.
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