Advertisements
Advertisements
प्रश्न
Calculate the mass of urea (NH2CONH2) required in making 2.5 kg of 0.25 molal aqueous solution.
Advertisements
उत्तर
Moles of urea = 0.25 mol
Mass of solvent (water) = 1 kg = 1000 g
Molar mass of urea (NH2CONH2) = 2(1 × 14 + 2 × 1) + 1 × 12 + 1 × 16
= 60 g mol−1
∴ Mass of urea in 1000 g of water = 0.25 mol × 60 g mol−1
= 15 g
Total mass of solution = 1000 + 15 g
= 1015 g
= 1.015 kg
Thus, 1.015 kg of solution contain urea = 15 g
∴ 2.5 kg of solution will require urea = `(15 "g")/(1.015 "kg") xx 2.5 "kg"`
= 36.95 g
= 37 g (approximately)
Hence, the mass of urea required is 37 g.
APPEARS IN
संबंधित प्रश्न
Calculate the mass percentage of benzene (C6H6) and carbon tetrachloride (CCl4) if 22 g of benzene is dissolved in 122 g of carbon tetrachloride.
Calculate the mole fraction of benzene in solution containing 30% by mass in carbon tetrachloride.
A solution of glucose in water is labelled as 10% w/w, what would be the molality and mole fraction of each component in the solution? If the density of solution is 1.2 g mL−1, then what shall be the molarity of the solution?
A solution is obtained by mixing 300 g of 25% solution and 400 g of 40% solution by mass. Calculate the mass percentage of the resulting solution.
Nalorphene (C19H21NO3), similar to morphine, is used to combat withdrawal symptoms in narcotic users. Dose of nalorphene generally given is 1.5 mg. Calculate the mass of 1.5 × 10−3 m aqueous solution required for the above dose.
When KOH solution is added to potassium dichromate solution the colour of solution
changes to yellow, because _______
(A) chromate ion changes to dichromate ion
(B) dichromate ion changes to chromate ion
(C) oxidation number of chromium changes from + 6 to + 4
(D) oxidation number of chromium changes from + 4 to +6
A sample of 12 M Concentrated hydrochloric acid has a density 1.2 M gL-1 calculate the molality.
The molarity of the solution containing 7.1 g of Na2SO4 in 100 ml of aqueous solution is ____________.
An aqueous solution of glucose is 10% in strength. The volume in which 1 g mole of it is dissolved, will be:
Mole fraction of the solute in a 1.00 molal aqueous solution is ____________.
Molarity of H2SO4 is 18 M. Its density is 1.8 g/ml. Hence molality is:
If N/10 50 ml H2SO4, N/3 30 ml HNO3, N/2 10 ml HCl is mixed and solution is made to 1 L. Then normality of the resultant solution is:
Cone. H2SO4 is 98% H2SO4 by mass has d = 1.84 g cm−3. Volume of acid required to make one litre of 0.1 M H2SO4 is:
Given below are two statements labelled as Assertion (A) and Reason (R).
Assertion (A): Molarity of a solution changes with temperature.
Reason (R): Molarity is a colligative property.
Select the most appropriate answer from the options given below:
The concentration of water molecules in pure water at 298 K is?
3.36 M sulphuric acid solution is 29% H2SO4 calculate the density of the solution.
Calculate the mass percent of benzene (CoH6) and carbon tetrachloride (ccl4) if 22 g of benzene is dissolved in 122 g of carbon tetrachloride.
A 6.50 molal solution of KOH (aq.) has a density of 1.89 g cm−3. The molarity of the solution is ______ mol dm−3. (Round off to the Nearest Integer)
[Atomic masses: K: 39.0 u; O: 16.0 u; H: 1.0 u]
A given solution of H2O2 is 30 volumes. Its concentration in terms of molarity is ______.
The depression in freezing point of water observed for the same amount of acetic acid, trichloroacetic acid and trifluoroacetic acid increases in the order given above. Explain briefly.
