if 6.0g of carbon is heated in air, the mass of the product obtained could either be 22.0g or 14.0g depending on the amount of air present , with what law will this be accordance ? (c=12 , o =16
Law of Multiple Proportions.
mols C = grams/atomic mass = 6/12 = 0.5
2C + O2 ==> 2CO
mols CO formed = 0.5 x (2 mols CO/2 mols C) = 0.5
grams C = 0.5 mols x molar mass CO = 0.5 x 28 = 14 g CO
OR
C + O2 ==> CO2
mols CO2 produced = 0.5 mols C x (1 mol CO2/1 mol C) = 0.5
grams CO2 = mols CO2 x molar mass CO2 = 0.5 x 44 = 22 g CO2
The Law of Multiple Proportions says that when two elements form more than one compound that the mass of one element that combines with a fixed amount of a seconc element the ratio is of small whole numbers. In this case, the amount of O that combines with a fixed amount of C (0.5 mol) the O will be in small whole numbers; i.e., 1 atom O to 2 atoms O. This law was proposed in 1804 by John Dalton.
This observation follows the Law of Definite Proportions, also known as the Law of Constant Composition. According to this law, a chemical compound always contains the same elements in the same proportion by mass, regardless of the sample size or source of the compound.
In this case, carbon (C) is reacting with oxygen (O) in the air to form a product. The possible masses of the products, 22.0g and 14.0g, correspond to different ratios of carbon to oxygen. This demonstrates that the mass of the product is determined by the ratio of the combining elements, providing evidence for the Law of Definite Proportions.
This situation can be explained by the law of conservation of mass, which states that matter cannot be created or destroyed in a chemical reaction. According to this law, the total mass of the reactants must be equal to the total mass of the products.
In this case, we have carbon (C) reacting with oxygen (O₂) in the air to form a product. The two possible product masses given are 22.0g and 14.0g. To determine which product mass is correct, we need to calculate the mass of oxygen required for each reaction and compare it to the amount of oxygen available.
The equation for the combustion of carbon in air is:
C + O₂ → CO₂
From the equation, we can see that for every mole of carbon (12g), we need one mole of oxygen (32g). So, the theoretical yield for the formation of carbon dioxide (CO₂) from 6.0g of carbon would be:
(6.0g C) / (12.0g C/mol) * (32.0g O₂/mol) = 16.0g CO₂
Therefore, if there is enough oxygen available, the correct product mass should be 16.0g. If the product mass obtained is 22.0g, it suggests that there is excess oxygen present, while a product mass of 14.0g suggests a limited amount of oxygen.
Hence, this situation is in accordance with the law of conservation of mass.