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Chemical Engineering Practice Test: Moles, Density & Concentration
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Moles, Density & Concentration topics include: Concepts of mole, density, specific gravity, flow rate and mass fraction. A mole is a unit of measurement for the amount of a substance. It is a base unit in the International System of Units (SI).  One mole contains 6.02214076×10²³ elementary entities, which can be atoms, molecules, ions, or other particles. This number is called the Avogadro number.  Chemists use moles to measure very small things like atoms, molecules, or other particles. For example, a mole of water contains Avogadro's number of H2O molecules. However, each water... Show more
Chemical Engineering Practice Test: Moles, Density & Concentration
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25 Questions

1. A mixture contains 10% CO, 40% CO2 and 50% H2O, what is the mass percent of CO2?
2. What is the specific gravity of a substance with mass 10 kg and volume 2 m3, with respect to the reference density 50 g/m3?
3. Which of the following is the unit of flow rate?
4. Which of the following is not the unit of concentration?
5. If the mole fraction of sodium is 0.25 in 9 moles of liquid carbon dioxide, what is the mass fraction of sodium?
6. What is the density of a substance of mass 10 grams and volume 5 liters?
7. A Composition of carbon dioxide, oxygen and nitrogen with mole ratio 1:2:5 with 4 moles of oxygen, enters a reactor with a flow rate of 100 kg/s, the ratio of rates of leaving the reactor of the three is 5:2:1, and 5 moles of nitrogen leaves the reactor, what is the total number of moles leaving the reactor?
8. What is the density of a liquid of mass 10 kg and contained in a cylinder of radius 5 m and surface area (excluding top and bottom) of 10π m2?
9. What is the mole fraction of sodium with moles n in a solution with moles of solvent N?
10. A gaseous mixture is composed of 20% CO2, 40% O2 and 40% N2. What is the mass fraction of N2?
11. What is the specific gravity of O2 at 27oC and 60 Pa with respect to 1 Kg/m3?
12. How many grams of NaCl represent 1 mole?
13. What is the concentration of a 22 grams of carbon dioxide occupying 0.5 m3 volume?
14. Which of the following has the same number of moles as in 398 grams of CuSO4?
15. How much Sodium is there in a solution with 10 Kg of solvent (Density = 5 Kg/m3) and concentration 4 molar?
16. If the mole fraction of SO2 in H2SO4 is 0.2, what is the ratio of mass of sulfur and oxygen in the solution?
17. 15 Kg/s of a fluid with density 5 Kg/m3 is passed into a tank of capacity 30 m3, how much time will it take to fill the tank?
18. A cylinder completely filled with water has density = 10 kg/m3 and volume 5 m3 , now a cube with side 1 m and density 25 kg/m3 is dipped into the cylinder with some water dropping out, what is the final density of cylinder?(neglect the mass of cylinder)
19. An empty vessel has with mass 5 kg with volume 0.1 m3, is now completely filled with a liquid of density 100 kg/m3, what is the final density of the cylinder?
20. If the mole fraction of 4.5 moles of solute is 0.5, what is the number of moles of solvent?
21. What is the API gravity of a substance with specific gravity 1?
22. What is the molarity of a solution with a mass of solute 10 kg mass and 100 liter volume?
23. API gravity is necessary for the calculation of specific gravity of petroleum products, because
24. What is the weight of 10 moles of a mixture with composition 15% O2, 25% SO2, 30% COCl2, 25% SO3 and 5% N2?
25. A solid of density d is dropped in a liquid of density D, if d>D then,