Chemistry - Mole Concept Question with Solution | TestHub

ChemistryMole ConceptAtomic mass/Average Atomic Mass/Average Molecular MassMedium2 minQB

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Passage / Comprehension

For a hypothetical chemical reaction represented by $3 A (g) ⟶ C (g) + D (g)$ , the following informations are known. Information

(i) At $t = 0$ , only 1 mole of A is present, and the gas has V.D. = 60.

(ii) At $t = 30$ min, the gaseous mixture consists of all three gases and has a vapor density = 75.

(iii) The molecular mass of C = 200.

Calculate:

Moles of substance C at $t = 30 min$ is.

Answer:

Solution:

Initial mass = 1 mole of A = 120 g (V.D. = 60 $\Rightarrow$ M = 120 g mol⁻¹).

At 30 min, V.D. = 75 $\Rightarrow$ Average molar mass = 150 g mol⁻¹.

Total moles at 30 min = $120/150 = 0.8$ mol.

Let $x$ mol of C be formed. Then total moles = $(1 - 3 x) + x + x = 1 - x$ .

So, $1 - x = 0.8 \Rightarrow x = 0.2$ mol.

Stream:JEESubject:ChemistryTopic:Mole ConceptSubtopic:Atomic mass/Average Atomic Mass/Average Molecular Mass

⏱ 2mℹ️ Source: QB

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