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### Topic: What is the approximate molecular weight of liquid?  (Read 1300 times)

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#### Win,odd Dhamnekar

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##### What is the approximate molecular weight of liquid?
« on: November 19, 2020, 08:46:19 AM »

Any science consists of the following process.
1) See 2) Hear 3) Smell if needed 4) Taste if needed
5) Think 6) Understand 7) Inference take decision [Believe or disbelieve, useful or useless, healthy or unhealthy, cause or effect, favorable or unfavorable, practical or theoretical, practically possible or practically impossible, true or false or  any other required criteria]

#### AWK

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##### Re: What is the approximate molecular weight of liquid?
« Reply #1 on: November 19, 2020, 09:02:12 AM »
You have all the information you need to calculate the molar mass from the ideal gas law.
AWK

#### Win,odd Dhamnekar

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##### Re: What is the approximate molecular weight of liquid?
« Reply #2 on: November 21, 2020, 10:17:36 AM »
Hello,
Weight of the unknown liquid inside the bulb after completion of reaction is 50.1879 grams - 50.0230 grams =0.1649 grams.

Volume of the water= 102.7535 grams - 50.0230 grams = 52.7305 grams = volume of the vapour of liquid after its immersion in oil bath at 423.15 K( 150° C) and 0.980 bar.

Using ideal gas law equation PV=nRT, $\frac{0.980 bar*0.0527305 liters}{0.0831447 bar*liters/(mol*K)*423.15 K}=0.001468787 mol$

Molar  weight of the unknown liquid =0.1649 grams/0.001468787 mol= 112.269 grams/mol. Its molecular weight is 1.86427e-22 u.

« Last Edit: November 21, 2020, 12:01:49 PM by Win,odd Dhamnekar »
Any science consists of the following process.
1) See 2) Hear 3) Smell if needed 4) Taste if needed
5) Think 6) Understand 7) Inference take decision [Believe or disbelieve, useful or useless, healthy or unhealthy, cause or effect, favorable or unfavorable, practical or theoretical, practically possible or practically impossible, true or false or  any other required criteria]

#### AWK

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##### Re: What is the approximate molecular weight of liquid?
« Reply #3 on: November 21, 2020, 12:51:26 PM »
The approximate molecular weight - 112.
AWK

#### Win,odd Dhamnekar

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##### Re: What is the approximate molecular weight of liquid?
« Reply #4 on: November 21, 2020, 02:31:49 PM »
Definitions of molecular mass, molecular weight, molar mass and molar weight

Molecular mass (molecular weight) is the mass of one molecule of a substance and is expressed in the unified atomic mass units (u). (1 u is equal to 1/12 the mass of one atom of carbon-12)

Molar mass (molar weight) is the mass of one mole of a substance and is expressed in g/mol
Any science consists of the following process.
1) See 2) Hear 3) Smell if needed 4) Taste if needed
5) Think 6) Understand 7) Inference take decision [Believe or disbelieve, useful or useless, healthy or unhealthy, cause or effect, favorable or unfavorable, practical or theoretical, practically possible or practically impossible, true or false or  any other required criteria]

#### mjc123

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##### Re: What is the approximate molecular weight of liquid?
« Reply #5 on: November 21, 2020, 03:00:05 PM »
Quote
Molar  weight of the unknown liquid =0.1649 grams/0.001468787 mol= 112.269 grams/mol. Its molecular weight is 1.86427e-22 u.
No. You have divided the molar mass by NA, which gives you the molecular weight in g. What is the molecular weight in u?

#### Win,odd Dhamnekar

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##### Re: What is the approximate molecular weight of liquid?
« Reply #6 on: November 21, 2020, 10:38:11 PM »
Oh! You are correct. AWK's answer is correct. Thanks for pointing out my mistake.   The molecular weight in u 1s 112.168
Any science consists of the following process.
1) See 2) Hear 3) Smell if needed 4) Taste if needed
5) Think 6) Understand 7) Inference take decision [Believe or disbelieve, useful or useless, healthy or unhealthy, cause or effect, favorable or unfavorable, practical or theoretical, practically possible or practically impossible, true or false or  any other required criteria]

#### mjc123

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##### Re: What is the approximate molecular weight of liquid?
« Reply #7 on: November 22, 2020, 06:22:35 AM »
Remember: The molecular weight in u is numerically equal to the molar mass in g/mol. (This follows from the definitions.)