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Science Clinic => Chemistry => Topic started by: Chloeellawright on Mar 21, 2021

Title: What is the percent by mass of ethanol (C2H5OH) in a 1.5-m aqueous solution?
Post by: Chloeellawright on Mar 21, 2021

Question 1

What is the molar mass of glucose if 22.5 g gives a freezing point of -0.930°C when dissolved in 250.0 g of water? If the empirical formula is CH2O, what is the molecular formula?


Question 2

What is the percent by mass of ethanol (C2H5OH) in a 1.5-m aqueous solution?
Title: What is the percent by mass of ethanol (C2H5OH) in a 1.5-m aqueous solution?
Post by: meryzewe on Mar 21, 2021

Answer 1

180. g/mol, C6H12O6

0.930°C = 1.86°C/m* (nmol/0.2500 kg);n= 0.125 mol

molar mass = 22.5 g/0.125 mol = 180. g/mol

empirical mass CH2O = 30.0;n= 180/30.0 = 6

molecular formula = 6(CH2O) = C6H12O6



Answer 2

6.5%

1.5m= 1.5 mol C2H5OH/1.0 kg water

1.5 mol * 46.07 g/mol = 69 g ethanol

69/(1000 + 69) = 6.5% 

Title: Re: What is the percent by mass of ethanol (C2H5OH) in a 1.5-m aqueous solution?
Post by: Saige Sterner on Dec 4, 2021
Thank you
Title: Re: What is the percent by mass of ethanol (C2H5OH) in a 1.5-m aqueous solution?
Post by: rucc0412 on Jan 25, 2022
Thank You
Title: Re: What is the percent by mass of ethanol (C2H5OH) in a 1.5-m aqueous solution?
Post by: sky _ on Jul 5, 2022
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