Advertisements
Advertisements
Question
If 4 g of \[\ce{NaOH}\] dissolves in 36 g of \[\ce{H2O}\], calculate the mole fraction of each component in the solution. Also, determine the molarity of solution (specific gravity of solution is 1g mL–1).
Advertisements
Solution
Molar mass of \[\ce{NaOH}\] = 40 g/mole
Molar mass of water = 18 g/ mole
Mass of \[\ce{NaOH}\] = 4 g
Number of moles of NaOH = `(4 g)/(40 g)` = 0.1 mol
Number of moles of H2O = `(36 g)/(18 g)` = 2 mol
Mole fraction of water = `(26 g)/("Number of moles of NaOH" + "Number of moles of" H_2O)`
Mole fraction of NaOH = `2/(0.1 + 2) = 2/2.1` = 0.95
Number of moles of `2/0.1 = 0.1/2.1` = 0.047
Number of moles of \[\ce{NaOH}\]
Mass of solution = Mass of solute + Mass of solvent
Mass of \[\ce{NaOH}\] + Mass of water = 4 g + 36 g = 40 g
Specific gravity of solution = 1 g/ml
1 litre = 1000 ml volume of solution = 40 ml
∴ 40 ml = 0.04 litre
Molarity = `"Number of moles of solute"/"Volume in litre" = (0.1 "mol")/(0.04 "litre")` = 2.5 M
APPEARS IN
RELATED QUESTIONS
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?
If the density of methanol is 0.793 kg L–1, what is its volume needed for making 2.5 L of its 0.25 M solution?
Dinitrogen and dihydrogen react with each other to produce ammonia according to the following chemical equation:
\[\ce{N2 (g) + 3H2 (g) → 2NH3 (g)}\]
(i) Calculate the mass of ammonia produced if 2.00 × 103 g dinitrogen reacts with 1.00 × 103 g of dihydrogen.
(ii) Will any of the two reactants remain unreacted?
(iii) If yes, which one and what would be its mass?
Explain the term mole fraction.
Explain the term molality
Solve the following problem:
Find out the molar mass of the following compounds:
Mohr’s salt [FeSO4(NH4)2SO4.6H2O]
(At. mass: Cu = 63.5; S = 32; O = 16; H = 1; Na = 23; C = 12; Fe = 56; N = 14)
Solve the following problem:
Write the following number in ordinary decimal form:
0.011 × 10−3
Solve the following problem:
Write the following number in ordinary decimal form:
14.3 × 10−2
Solve the following problem:
Perform the following calculation. Round off your answer to two digits.
`1/(3.40xx10^24)`
Solve the following problem:
Perform the following calculation. Round off your answer to two digits.
`33/(9.00xx10^-4)`
Solve the following problem:
Your laboratory partner was given the task of measuring the length of a box (approx 5 in) as accurately as possible, using a metre stick graduated in milimeters. He supplied you with the following measurements:
12.65 cm, 12.6 cm, 12.65 cm, 12.655 cm, 126.55 mm, 12 cm.
State which of the measurements you would accept, giving the reason.
Solve the following problem:
The hourly energy requirements of an astronaut can be satisfied by the energy released when 34 grams of sucrose are “burnt” in his body. How many grams of oxygen would be needed to be carried in space capsule to meet his requirement for one day?
Name the process associated with the following
A drop of ink placed on the surface of water contained in a glass spreads throughout the water.
Calculate the mass of sodium sulphate required to prepare its 20% (mass percent) solution in 100g of water?
What will be the molarity of a solution, which contains 5.85 g of NaCl(s) per 500 mL?
Which of the following solutions have the same concentration?
(i) \[\ce{20 g of NaOH in 200 mL of solution}\]
(ii) \[\ce{0.5 mol of KCl in 200 mL of solution}\]
(iii) \[\ce{40 g of NaOH in 100 mL of solution}\]
(iv) \[\ce{20 g of KOH in 200 mL of solution}\]
What quantity (in mL) of a 45% acid solution of a monoprotic strong acid must be mixed with a 20% solution of the same acid to produce 800 mL of a 29.875% acid solution?
250 g solution of D-glucose in water contains 10.8% of carbon by weight. The molality of the solution is nearest to ______.
(Given: Atomic weights are H, 1u; C, 12u; O, 16u)
The molality of solution containing 15.20 g of urea, (molar mass = 60) dissolved in 150 g or water is ______.
