Class 12 Chemistry - Chapter Solutions NCERT Solutions | Calculate the mass of urea (NH2CONH2) re
Calculate the mass of urea (NH2CONH2) required in making 2.5 kg of 0.25 molal aqueous solution.
Molar mass of urea (NH2CONH2) = 2 (1 × 14 + 2 × 1) + 1 × 12 + 1 × 16
= 60 g mol - 1
0.25 molar aqueous solution of urea means:
1000 g of water contains 0.25 mol = (0.25 × 60) g of urea
= 15 g of urea
That is, (1000 + 15) g of solution contains 15 g of urea
Therefore, 2.5 kg (2500 g) of solution contains = (15 X 2500) / (1000+15) g
= 36.95 g
= 37 g of urea (approximately)
Hence, mass of urea required = 37 g
More Questions From Class 12 Chemistry - Chapter Solutions
- Q:-
A 5% solution (by mass) of cane sugar in water has freezing point of 271 K. Calculate the freezing point of 5% glucose in water if freezing point of pure water is 273.15 K.
- Q:-
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?
- Q:-
Henry's law constant for CO2 in water is 1.67 x 108Pa at 298 K. Calculate the quantity of CO2in 500 mL of soda water when packed under 2.5 atm CO2 pressure at 298 K.
- Q:-
Calculate the mass of a non-volatile solute (molar mass 40 g mol-1) which should be dissolved in 114 g octane to reduce its vapour pressure to 80%.
- Q:-
The vapour pressure of pure liquids A and B are 450 and 700 mm Hg respectively, at 350 K. Find out the composition of the liquid mixture if total vapour pressure is 600 mm Hg. Also find the composition of the vapour phase.
- Q:-
Calculate the mole fraction of benzene in solution containing 30% by mass in carbon tetrachloride.
- Q:-
How many mL of 0.1 M HCl are required to react completely with 1 g mixture of Na2CO3 and NaHCO3 containing equimolar amounts of both?
- Q:-
H2S, a toxic gas with rotten egg like smell, is used for the qualitative analysis. If the solubility of H2S in water at STP is 0.195 m, calculate Henry's law constant.
- Q:-
An aqueous solution of 2% non-volatile solute exerts a pressure of 1.004 bar at the normal boiling point of the solvent. What is the molar mass of the solute?
- Q:-
Boiling point of water at 750 mm Hg is 99.63°C. How much sucrose is to be added to 500 g of water such that it boils at 100°C.Molal elevation constant for water is 0.52 K kg mol-1.
Popular Questions of Class 12 Chemistry
- Q:-
For the reaction R → P, the concentration of a reactant changes from 0.03 M to 0.02 M in 25 minutes. Calculate the average rate of reaction using units of time both in minutes and seconds.
- Q:-
Write the formulas for the following coordination compounds:
(i) Tetraamminediaquacobalt (III) chloride
(ii) Potassium tetracyanonickelate(II)
(iii) Tris(ethane-1,2-diamine) chromium(III) chloride
(iv) Amminebromidochloridonitrito-N-platinate(II)
(v) Dichloridobis(ethane-1,2-diamine)platinum(IV) nitrate
(vi) Iron(III) hexacyanoferrate(II)
- Q:-
(i) Write structures of different isomeric amines corresponding to the molecular formula, C4H11N
(ii) Write IUPAC names of all the isomers.
(iii) What type of isomerism is exhibited by different pairs of amines?
- Q:-
Why are solids rigid?
- Q:-
Write any two characteristics of Chemisorption.
- Q:-
Write the structures of the following compounds.
(i) α-Methoxypropionaldehyde
(ii) 3-Hydroxybutanal
(iii) 2-Hydroxycyclopentane carbaldehyde
(iv) 4-Oxopentanal
(v) Di-sec-butyl ketone
(vi) 4-Fluoroacetophenone
- Q:-
Which of the ores mentioned in Table 6.1 can be concentrated by magnetic separation method?
- Q:-
Why are pentahalides more covalent than trihalides?
- Q:-
Silver atom has completely filled d orbitals (4d10) in its ground state. How can you say that it is a transition element?
- Q:-
Glucose or sucrose are soluble in water but cyclohexane or benzene (simple six membered ring compounds) are insoluble in water. Explain.
Recently Viewed Questions of Class 12 Chemistry
- Q:-
Why is H2O a liquid and H2S a gas?
- Q:-
The chemistry of the actinoid elements is not so smooth as that of the Lanthanoids. Justify this statement by giving some examples from the oxidation state of these elements.
- Q:-
Explain how vacancies are introduced in an ionic solid when a cation of higher valence is added as an impurity in it.
- Q:-
Gold (atomic radius = 0.144 nm) crystallises in a face-centred unit cell. What is the length of a side of the cell?
- Q:-
Explain why inspite of nearly the same electronegativity, oxygen forms hydrogen bonding while chlorine does not.
- Q:-
Why do soaps not work in hard water?
- Q:-
What is meant by unidentate, didentate and ambidentate ligands? Give two examples for each.
- Q:-
How does ammonia react with a solution of Cu2+?
- Q:-
Calculate the emf of the cell in which the following reaction takes place:
Ni(s) + 2Ag+ (0.002 M) → Ni2+ (0.160 M) + 2Ag(s)
Given that Eøcell = 1.05 V
- Q:-
Knowing the electron gain enthalpy values for O → O- and O → O2- as -141 and 702 kJ mol-1 respectively, how can you account for the formation of a large number of oxides having O2- species and not O-? (Hint: Consider lattice energy factor in the formation of compounds).
10 Comment(s) on this Question
Thanks saral study
That's awesome thank you so much
Thank you.
Thank you very much saral study
Thanks saral study.
Thanks
Please clear all method don't skip any method
Thanks
But in ncert there i wrong answer
Gone out of mindðð ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡ð¡
- All Chapters Of Class 12 Chemistry
- All Subjects Of Class 12