Average atomic weight of an element M is 51.7. If two isotopes of $M, M^{50}$ and $M^{52}$ are present, then percentage of occurrence of $M^{50}$ in nature will be.
- 85%
- 15%
- 50%
- 100%
The Correct Option is B
Solution and Explanation
Let's assume $M^{50}$ occurs with $x\%$.
Hence, $M^{52} = (100 - x)\%$
Average atomic weight
$51.7=\frac{x \times M^{50}+\left(100-x\right)\times M^{52}}{100}$
$51.7=\frac{x \times50+\left(100-x\right)52}{100}$
$5170 = 5200 - 2x$
$2x=5200-5170$
$x=15$
Hence, $\%$ of $M^{50}=15\%$
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Concepts Used:
Laws of Chemical Combination
Basic Laws of Chemical Combinations:
The five basic laws of chemical combination for elements and compounds are given below.
Law of Conservation of Mass:
The Law of conservation of mass or the principle of mass conservation states that for any system closed to all transfers of matter and energy, the mass of the system must remain constant over time, as the system's mass cannot change, so the quantity can neither be added nor be removed.
Law of Definite Proportions:
The Law of definite proportions, sometimes called Proust's law, or the law of constant composition states that a given chemical compound always contains its component elements in a fixed ratio and does not depend on its source and method of preparation
Law of Multiple proportions:
The Law of multiple proportions states that if two elements form more than one compound, then the ratios of the masses of the second element which combine with a fixed mass of the first element will always be ratios of small whole numbers.
Gay Lussac’s Law of Gaseous Volumes:
Gay Lusaacc's law of gaseous volume states that the pressure of a given mass of gas varies directly with the absolute temperature when the volume is kept constant.
Avogadro’s Law:
Avogadro-Ampère's hypothesis is an experimental gas law relating the volume of a gas to the amount of substance of gas present.