The question describes two different compounds (water and hydrogen peroxide) formed from the same two elements (hydrogen and oxygen). It provides the masses of oxygen that combine with a fixed mass of hydrogen in these two compounds. We need to identify the chemical law that this observation illustrates.
D) Law of Multiple Proportions — ratio of oxygen masses (16:32 = 1:2) is a simple whole number ratio. This law is directly illustrated by the given data. When hydrogen and oxygen combine to form water and hydrogen peroxide, for a fixed mass of hydrogen (2 g), the masses of oxygen (16 g and 32 g) are in a simple whole number ratio of 1:2.
The Law of Multiple Proportions, proposed by John Dalton, is a fundamental concept in chemistry that helped lay the groundwork for atomic theory. To answer this question, we need to understand what this law states and how its implications support the idea of atoms.
Correct Option: C) Simple whole number ratios of combining masses directly indicate that elements combine as discrete indivisible atoms in fixed numerical ratios — fractional atoms would give fractional ratios.
The question asks for the ratio of oxygen masses in sulphur dioxide (SO₂) and sulphur trioxide (SO₃) when the mass of sulphur is fixed at 32 g. This scenario directly relates to the Law of Multiple Proportions, which 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 ratios of small whole numbers.
Identify the given information for SO₂:
Identify the given information for SO₃:
Calculate the ratio of oxygen masses:
C) 32:48 = 2:3 (a simple whole number ratio — illustrating the Law of Multiple Proportions). This option correctly identifies the ratio of oxygen masses as 2:3, which is obtained by simplifying 32:48. This also correctly points out that this illustrates the Law of Multiple Proportions, as the masses of oxygen combining with a fixed mass of sulphur are in a simple whole number ratio.
The question asks to identify the scientist who proposed Gay-Lussac's Law of Combining Volumes and the year it was proposed. This requires knowledge of fundamental chemical laws and their historical context.
Correct Option: B) Joseph Louis Gay-Lussac (French chemist), 1808
Joseph Louis Gay-Lussac, a French chemist, proposed the Law of Combining Volumes in 1808. This law is a cornerstone of stoichiometry and helped in the development of atomic theory.
The question asks for the correct statement of Gay-Lussac's Law of Combining Volumes. This law describes the volumetric relationships between gaseous reactants and products in a chemical reaction. We need to identify the option that accurately defines this principle.
A) When gases combine or are produced in a chemical reaction, they do so in volumes that bear a simple whole number ratio to one another and to the products (if gaseous), all measured at the same temperature and pressure. This statement is the precise definition of Gay-Lussac's Law of Combining Volumes.
The question asks about the volume ratio of reactants and products in the formation of water vapour from hydrogen and oxygen gases, illustrating Gay-Lussac's Law of Gaseous Volumes. This law states that when gases react, they do so in volumes that bear a simple whole-number ratio to one another, and to the volume of the gaseous products, provided that all volumes are measured at the same temperature and pressure.
B) 2 : 1 : 2 (two volumes of H₂ + one volume of O₂ → two volumes of water vapour) — This option correctly reflects the stoichiometric coefficients from the balanced chemical equation for the formation of water vapour, which is consistent with Gay-Lussac's Law of Gaseous Volumes.