Chemistry Class 11 NCERT Solutions: Chapter 1 Some Basic Concepts of Chemistry Part 4

Q: 10. In three moles of ethane Equation calculate following:

This structure of three moles of ethan C2H6

Structure of Ethane

This structure of three moles of ethan C2H6

(i) Number of moles of carbon atoms

(ii) Number of moles of hydrogen atoms

(iii) Number of molecules of ethane

Answer:

(i) 1 mole of Equation contains Equation moles of carbon atoms.

∴ Number of moles of carbon atoms in Equation moles of Equation

Equation

(ii) 1 mole of Equation contains 6 moles of hydrogen atoms.

∴ Number of moles of carbon atoms in Equation moles of Equation

Equation

(iii) 1 mole of Equation contains Equation molecules of ethane.

∴ Number of molecules in 3 moles of Equation

Equation

Q: 11. What is the concentration of sugar Equation

This structure is disaccharides sucrose example

Structure of Disaccharides (Double Sugars)

This structure is disaccharides sucrose example

In Equation are dissolved in enough water to make a final volume up to Equation ?

Answer:

Molarity (M) of a solution is given by,

Equation

Equation

Equation

Equation

Equation

Equation

∴ Molar concentration of sugar Equation

Image showing Sugar is sucrose, a molecule composed

Image Showing Structure of Concetration of Sugar

Image showing Sugar is sucrose, a molecule composed

Q: 12. If the density of methanol is Equation what is its volume needed for making Equation of its 0.25 M solution?

Image showing methanol structure.

Image Showing Methanol Structure.

Image showing methanol structure.

Answer:

Molar mass of methanol Equation

Equation

Equation

Molarity of methanol solution Equation

Equation

(Since density is mass per unit volume)

Applying,

Equation

(Given solution) (Solution to be prepared)

Equation

Equation

Equation

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