Laws of chemical combination and stoichiometry - One Line Questions

1. Percent yield is calculated as: — (Actual yield / Theoretical yield) x 100
2. What is the number of moles in 24.5 g of H2SO4? (Atomic masses: H=1, S=32, O=16) — 0.25 moles
3. What is the number of moles in 50 g of CaCO3? (Atomic masses: Ca=40, C=12, O=16) — 0.5 moles
4. The balanced equation for the combustion of methane is CH4 + 2O2 -> CO2 + 2H2O. If 1 mole of CH4 is completely burned, how many moles of O2 are consumed? — 2 moles
5. The reaction is 2KClO3 -> 2KCl + 3O2. If 1 mole of KClO3 decomposes, how many moles of O2 are produced? — 1.5 moles
6. Consider the reaction: N2(g) + 3H2(g) -> 2NH3(g). According to Gay-Lussac's Law, 1 volume of N2 reacts with 3 volumes of H2 to produce: — 2 volumes of NH3
7. Carbon forms two oxides, CO and CO2. If we take a fixed mass of carbon (say 12 g), the mass of oxygen that combines with it are 16 g in CO and 32 g in CO2. The ratio of masses of oxygen in CO2 to CO is: — 2:1
8. How many grams of NaCl can be produced from 10 g of Na and 10 g of Cl2 according to the reaction 2Na + Cl2 -> 2NaCl? (Atomic masses: Na=23, Cl=35.5) — 26.5 g
9. What is the volume of 2 moles of an ideal gas at STP? — 44.8 L
10. What is the molar mass of water (H2O)? (Atomic masses: H = 1, O = 16) — 18 g/mol
11. What is the mass of 1 mole of oxygen gas (O2)? (Atomic mass of O = 16) — 32 grams
12. What is the volume occupied by 1 mole of any ideal gas at Standard Temperature and Pressure (STP: 0°C and 1 atm)? — 22.4 L
13. What is the number of molecules in 11.2 L of any ideal gas at STP? — 3.011 x 10^23
14. In the reaction S + O2 -> SO2, if 32 g of sulfur reacts with excess oxygen, what mass of SO2 is produced? (Atomic masses: S=32, O=16) — 64 g
15. Consider the reaction 2H2 + O2 -> 2H2O. If 4 g of H2 react with 32 g of O2, what is the mass of water formed? (Atomic masses: H=1, O=16) — 36 g
16. A reaction has a theoretical yield of 80 g and an actual yield of 60 g. What is the percent yield? — 75%
17. A reaction produces 10 g of product. If the percent yield is 50%, what was the theoretical yield? — 20 g
18. When 10 grams of a reactant A react completely with 5 grams of reactant B, what will be the total mass of the products formed? — 15 grams
19. If 100 g of A reacts with B to produce 150 g of product, what is the mass of B that reacted? — 50 g
20. If the theoretical yield of a reaction is 50 g and the actual yield is 40 g, what is the percent yield? — 80%
21. Avogadro's number is approximately: — 6.022 x 10^23
22. What is the mass of 0.5 moles of Nitrogen gas (N2)? (Atomic mass of N = 14) — 14 g
23. If 1 gram of Hydrogen combines with 8 grams of Oxygen to form water, then 1 gram of Hydrogen will combine with how many grams of Chlorine to form HCl? — 35.5 grams
24. What is the molar mass of glucose (C6H12O6)? (Atomic masses: C=12, H=1, O=16) — 180 g/mol
25. Consider the reaction: 2A + 3B -> 4C. If 4 moles of A react with 4 moles of B, which is the limiting reactant? — A
26. If the molecular formula of a compound is C6H12O6, what is its empirical formula? — CH2O
27. The mole is the SI unit for amount of substance. One mole of any substance contains the same number of elementary entities as there are atoms in exactly 12 grams of: — Carbon-12
28. What is the empirical formula of a compound containing 40% Carbon, 6.67% Hydrogen, and 53.33% Oxygen by mass? — CH2O
29. The empirical formula of a compound is CH2O. If its molar mass is 180 g/mol, what is its molecular formula? — C6H12O6
30. Which reactant is completely consumed first in a chemical reaction and thus determines the amount of product formed? — Limiting reactant
31. In the reaction 2H2 + O2 -> 2H2O, if 4 g of H2 react with 32 g of O2, which reactant is in excess? — Hydrogen
32. The Law of Multiple Proportions was proposed by: — John Dalton
33. The Law of Conservation of Mass is attributed to which scientist? — Antoine Lavoisier
34. Which law states that if two elements combine to form more than one compound, the masses of one element that combine with a fixed mass of the other element are in a ratio of small whole numbers? — Law of Multiple Proportions
35. Which law is a direct consequence of Avogadro's hypothesis when dealing with gaseous reactions? — Gay-Lussac's Law of Gaseous Volumes
36. Which law provides the foundation for understanding the composition of compounds at a molecular level? — Law of Definite Proportions
37. If 6 liters of a gas react with 12 liters of another gas to produce 18 liters of a product, this is consistent with which law? — Gay-Lussac's Law of Gaseous Volumes
38. The law that relates the masses of different elements that combine with the same mass of a third element is: — Law of Reciprocal Proportions
39. Which of the following is NOT a law of chemical combination? — Dalton's Atomic Theory
40. If 2 liters of CO react with 1 liter of O2 to form 2 liters of CO2 (according to 2CO + O2 -> 2CO2), this illustrates: — Gay-Lussac's Law of Gaseous Volumes
41. Which law states that matter can neither be created nor destroyed in a chemical reaction? — Law of Conservation of Mass
42. Avogadro's Hypothesis states that equal volumes of all gases, under the same conditions of temperature and pressure, have the same: — Number of molecules
43. In the balanced chemical equation 2H2 + O2 -> 2H2O, the coefficients represent the ratio of: — Moles
44. Stoichiometry is derived from Greek words 'stoicheion' (element) and 'metron' (measure). It deals with the quantitative relationships between reactants and products in a: — Chemical reaction
45. Gay-Lussac's Law of Gaseous Volumes states that when gases react together, they do so in volumes which bear a simple whole number ratio to one another and to the volumes of the products, provided all gases are at the same: — Pressure and Temperature
46. The term 'stoichiometric amount' refers to the exact molar ratio required for complete reaction according to the balanced chemical equation, meaning there is no: — Reactant left over
47. The Law of Reciprocal Proportions states that if two different elements separately combine with a third element, then the masses of these two elements which combine with the same mass of the third element bear to each other a ratio of: — Simple whole numbers
48. What is the theoretical yield of a reaction? — The maximum amount of product that can be formed based on the limiting reactant
49. Molar volume of a gas at STP is defined as: — The volume occupied by 1 mole of gas at 0°C and 1 atm
50. According to the Law of Definite Proportions, a chemical compound always contains its constituent elements in a fixed ratio by: — Mass
All One Line Questions
E-Book Laws of chemical combination and stoichiometry Online Test Laws of chemical combination and stoichiometry Question Bank Laws of chemical combination and stoichiometry