Chemical Engineering

Concentration

Question 1
Marks : +2 | -2
Pass Ratio : 33%
How much Sodium is there in a solution with 10 Kg of solvent (Density = 5 Kg/m3) and concentration 4 molar?
23 grams
92 grams
184 grams
276 grams
Explanation:
Volume of solvent = 10/5 = 2 m3, => moles of sodium = 4*2 = 8 moles, => mass of sodium = 8*23 = 184 grams.
Question 2
Marks : +2 | -2
Pass Ratio : 33%
What is the concentration of a solution with 10 grams of calcium in 1000 m3 of water?
150 ppm
250 ppm
800 ppm
1000 ppm
Explanation:
Moles of calcium = 10/40 =0.25, => concentration in ppm = (0.25/1000)*106 = 250 ppm.
Question 3
Marks : +2 | -2
Pass Ratio : 33%
What is the concentration of a 22 grams of carbon dioxide occupying 0.5 m3 volume?
1 mole/m3
2 mole/m3
11 mole/m3
22 mole/m3
Explanation:
Moles of carbon dioxide = 22/44 = 0.5, => concentration = 0.5/0.5 = 1 mole/m3.
Question 4
Marks : +2 | -2
Pass Ratio : 33%
A 5 molar solution is 27.75% CaCl2 by mass, what is the density of the solution?
1 g/cm3
2 g/cm3
3 g/cm3
4 g/cm3
Explanation:
Let the mass of Solution be 100 grams, => moles of CaCl2 = 27.75/111 = 0.25, Density of solution = 5*(100/0.25) = 2000 kg/m3 = 2 g/cm3.
Question 5
Marks : +2 | -2
Pass Ratio : 33%
What is the molarity of a solution with a mass of solute 10 kg mass and 100 liter volume?
0.1 molar
1 molar
10 molar
100 molar
Explanation:
Molarity = 10/100 = 0.1 molar.
Question 6
Marks : +2 | -2
Pass Ratio : 33%
What is the molarity of the mixture of two solution, first solution 4 M and 10 liter and second solution 2 M and 40 liter?
1.2 M
2.4 M
4.8 M
9.2 M
Explanation:
Molarity of mixture = (M1V1 + M2V2)/(V1 + V2) = (4*10 + 2*40)/ (10 + 40) = 2.4 M.
Question 7
Marks : +2 | -2
Pass Ratio : 33%
A solution with density 1 g/cm3 has 98 grams of H2SO4 in 402 grams of water, what is the concentration of solution?
1 molar
2 molar
3 molar
4 molar
Explanation:
Moles of H2SO4 = 98/98 = 1, => concentration of solution = 1/(500/1) = 2*10-6 mole/cm3 = 2 molar.
Question 8
Marks : +2 | -2
Pass Ratio : 33%
Which of the following is not the unit of concentration?
Mole/m3
Molar
N/m3
ppm
Explanation:
Concentration is moles per unit volume or mass per unit volume, so N/m3 cannot be a unit of concentration.
Question 9
Marks : +2 | -2
Pass Ratio : 33%
What is the concentration of 100 lbs. of solution occupying 25 m3 of volume?
1.8 Kg/m3
2.7 Kg/m3
4 Kg/m3
8 Kg/m3
Explanation:
Mass of solution = 100*0.453 = 45.3 kg, => Concentration of solution = 45.3/25 = 1.8 kg/m3.
Question 10
Marks : +2 | -2
Pass Ratio : 33%
A solution with density 2 g/cm3, concentration 1 molar and weight 500 grams, then what is the mass of HNO3 in the solution?
63 grams
126 grams
189 grams
252 grams
Explanation:
Moles of HNO3 = 1/(500/2000) = 4, = > mass of HNO3 = 4*63 = 252 grams.