What is the concentration of sugar (C12H22O11) in mol L–1 if its 20 g are dissolved in enough water to make a final volume up to 2 L?
Molarity (M) of a solution is given by,
`="Number of moles of solute"/"Volume of solution in Litres"`
`="Mass of sugar/molar mass of sugar"/(2 "L")`
`=(20 "g"//[(12xx12)+(1xx22)+(11xx16)]"g")/(2"L")`
`=(20 "g"//342 "g")/(2"L")`
`=(0.0585" mol")/(2"L")`
= 0.02925 mol L-1
∴ Molar concentration of sugar = 0.02925 mol L–1
Concept: Stoichiometry and Stoichiometric Calculations - Reactions in Solutions
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Kiran R.
asked • 01/03/15This question is from CBSE 11th class portion.It was asked in my Half-Yearly examination..
2 Answers By Expert Tutors
To the nearest .1, the molecular weights of each element are:
So the molecular weight of the sugar is 12 x 12 + 22 x 1 + 11 x 16 = 342. So 20 grams is 20 / 342 = .058 moles. If the solution contains 2 liters, then the concentration is .058 / 2 = .029 mol / L
Kiran R. This question is from CBSE 11th class portion.It was asked in my Half-Yearly examination..
2 Answers By Expert Tutors
To the nearest .1, the molecular weights of each element are: So the molecular weight of the sugar is 12 x 12 + 22 x 1 + 11 x 16 = 342. So 20 grams is 20 / 342 = .058 moles. If the solution contains 2 liters, then the concentration is .058 / 2 = .029 mol / L
Chris P. answered • 01/05/15
Experienced SCIENCE and EMS Education Tutor
The easiest way to answer this question is to first figure out the molar mass of the sugar in question. To do this multiply the number of individual atoms for a given element by its atomic mass.
12 X 12.01 g/mol = 144.12 g/mol C
22 X 1.008 g/mol = 22.176 g/mol H
11 X 16.00 g/mol = 176.00 g/mol O
Total = 342.296 ~ 342.30 g/mol C12H22O11
These numbers can be found using the periodic table
The second step is to take the number of grams of sugar you have; in this case 20g and divide it by the molar mass of the sugar 342.30 g/mol.
The Third step is to take the number of moles and divide it by your total volume of 2L. Remember that for liquid concentrations, it is always in units of moles/L; this is also the definition of Molarity.
0.058 mol = 0.029 mol/L OR 0.029M C12H22O11
I hope this clears up any confusion.
What is the concentration of sugar (C12H22O11) in mol L–1 if its 20 g are dissolved in enough water to make a final volume up to 2 L?
Molarity (M) of a solution is given by,
`="Number of moles of solute"/"Volume of solution in Litres"`
`="Mass of sugar/molar mass of sugar"/(2 "L")`
`=(20 "g"//[(12xx12)+(1xx22)+(11xx16)]"g")/(2"L")`
`=(20 "g"//342 "g")/(2"L")`
`=(0.0585" mol")/(2"L")`
= 0.02925 mol L-1
∴ Molar concentration of sugar = 0.02925 mol L–1
Concept: Stoichiometry and Stoichiometric Calculations - Reactions in Solutions
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What Is The Concentration Of Sugar (C12H22O11) In Mol L–1 If Its 20 G Are Dissolved In Enough Water To Make A Final Volume Up To 2 L? Chemistry Q&A
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