EASY
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6.02×1020molecules of urea are present in 100 mL of its solution. The concentration of urea solution is

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Important Questions on Some Basic Concepts of Chemistry

MEDIUM
Dissolving 120 g of a compound of (mol. wt. 60) in 1000 g of water gave a solution of density 1.12 g/mL. The molarity of the solution is :
MEDIUM
A solution (5 mL) of an acid X is completely neutralized by y mL of 1M NaOH. The same volume (y mL) of 1M NaOH is required to neutralize 10 mL of 0.6 M H2SO4 completely. The normality (N) of the acid X is
EASY
Which of the following is dependent on temperature?
MEDIUM
The standard enthalpies of formation of H2O(l) and CO2(g) are respectively -286kJ mol-1 and -394kJ mol-1. If the standard heat of combustion of CH4(g) is -891kJ mol-1, then the standard enthalpy of formation of CH4(g) is
EASY
What is mole fraction of the solute in a 1.00 m aqueous solution?
MEDIUM
A solution is prepared by dissolving 20g NaOH in 1250mL of a solvent of density 0.8g/mL. Then the molality of the solution is;
HARD
What quantity (in mL) of a 45% acid solution of a mono-protic strong acid must be mixed with a 20% solution of the same acid to produce 800 mL of a 29.875% acid solution?
EASY
Calculate the concentration of the 2%(w/w)NaCl solution in terms of molality.
EASY
The weight percent of sucrose (formula weight =342 g mol-1 ) in an aqueous solution is 3.42. The density of the solution is 1 g mL-1, the concentration of sucrose in the solution in mol L-1 is
HARD
If Avogadro's number is A0 , the number of sulphur atoms present in 200 mL of 1N H2SO4 is
MEDIUM
In which one of the following reactions, entropy decreases?
MEDIUM
The mole fraction of a solvent in aqueous solution of a solute is 0.8. The molality (in mol kg-1 ) of the aqueous solution is:
MEDIUM
The mole fraction of glucose C6H12O6 in an aqueous binary solution is 0.1. The mass percentage of water in it, to the nearest integer, is
EASY
What would be the molality of 20% (mass/mass) aqueous solution of KI ? (molar mass of KI=166 g mol-1 )
EASY
Dissolving 120 g of urea in 1000 g of water gave a solution of density 1.15g/mL. The molarity of the solution is:
EASY
A litre of seawater (which weighs 1030 g) contains 6×10-3 g of dissolved oxygen. The concentration of dissolved oxygen in ppm is:
MEDIUM
A gas mixture contains 25% He and 75% CH4 by volume at a given temperature and pressure. The percentage by mass of methane in the mixture is approximately ___ .
MEDIUM
The molality of solution containing 15.20 g of urea, (molar mass = 60) dissolved in 150 g of water is
EASY
A solution of sodium sulphate contains 92 g of Na+ ions per kilogram of water. The molality of Na+ ions in that solution in mol kg-1 is:
EASY
8 g of NaOH is dissolved in 18g of H2O. Mole fraction of NaOH in solution and molality (in  mol kg-1) of the solution respectively are: