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NEET CHEMISTRYSome Basic Concepts of ChemistryMedium

Question

The total number of electrons present in 1.6 g1.6\text{ g} of methane is:

A

6.02×10236.02 \times 10^{23}

B

6.02×10226.02 \times 10^{22}

C

6.02×10216.02 \times 10^{21}

D

4.02×10204.02 \times 10^{20}

Step-by-Step Solution

First, calculate the number of moles of methane (CH4\text{CH}_4). Molar mass of CH4=12+(4×1)=16 g/mol\text{CH}_4 = 12 + (4 \times 1) = 16\text{ g/mol}. Moles of CH4=Given MassMolar mass=1.6 g16 g/mol=0.1 mol\text{CH}_4 = \frac{\text{Given Mass}}{\text{Molar mass}} = \frac{1.6\text{ g}}{16\text{ g/mol}} = 0.1\text{ mol}.

Next, calculate the number of molecules of methane in 0.1 mol0.1\text{ mol}. Number of molecules = Moles×NA=0.1×(6.02×1023)=6.02×1022\text{Moles} \times N_A = 0.1 \times (6.02 \times 10^{23}) = 6.02 \times 10^{22} molecules.

Now, determine the number of electrons in one molecule of CH4\text{CH}_4. A carbon atom (atomic number 6) has 66 electrons, and each hydrogen atom (atomic number 1) has 11 electron. So, one CH4\text{CH}_4 molecule contains 6+4(1)=106 + 4(1) = 10 electrons.

Finally, calculate the total number of electrons in 1.6 g1.6\text{ g} of methane. Total electrons = Number of molecules ×\times Electrons per molecule = (6.02×1022)×10=6.02×1023(6.02 \times 10^{22}) \times 10 = 6.02 \times 10^{23} electrons.

Exam Context & Concepts Covered

This question aligns with the NEET CHEMISTRY syllabus, specifically targeting concepts from Some Basic Concepts of Chemistry. Mastering this topic is crucial for scoring well in the upcoming medical entrance examinations. Solving conceptually related problems will help you understand the nuances of these concepts and improve your problem-solving speed.

CHEMISTRYSome Basic Concepts of Chemistrynumberelectronspresentmethane

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