Number of electrons present in 8.4 g of CO is:
A. 0.3 N_A
B. 1.4 N_A
C. 2.8 N_A
D. 4.2 N_A
Answer (2)
The number of electrons in 8.4 g of carbon monoxide (CO) can be calculated through molar mass and Avogadro's number. The final calculation shows approximately 2.8 times Avogadro's number of electrons. Therefore, the correct answer is C. 2.8 N_A .
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To determine the number of electrons present in 8.4 g of carbon monoxide (CO), we'll break the problem down into steps.
Calculate the moles of CO:
The molar mass of CO is the sum of the molar masses of carbon (C) and oxygen (O):
Carbon (C) has an atomic mass of approximately 12 g/mol.
Oxygen (O) has an atomic mass of approximately 16 g/mol.
Thus, the molar mass of CO = 12 g/mol + 16 g/mol = 28 g/mol.
The number of moles of CO in 8.4 g is:
Moles of CO = 28 g/mol 8.4 g = 0.3 moles
Calculate the number of molecules of CO using Avogadro's number ( N A ):
Avogadro's number ( N A ) is approximately 6.022 × 1 0 23 molecules/mol. Therefore, the number of molecules of CO in 0.3 moles is:
Number of molecules = 0.3 × 6.022 × 1 0 23 = 1.807 × 1 0 23
Calculate the total number of electrons in these molecules:
Each CO molecule consists of one carbon (C) atom and one oxygen (O) atom.
Carbon (C) has 6 electrons.
Oxygen (O) has 8 electrons.
Therefore, each CO molecule has a total of 14 electrons:
6 ( from C ) + 8 ( from O ) = 14 electrons per CO molecule
So, the total number of electrons in 1.807 x 10^{23} molecules is:
1.807 × 1 0 23 molecules × 14 electrons/molecule = 2.53 × 1 0 24 electrons
Express the number of electrons in terms of N A :
2.53 × 1 0 24 ≈ 4.2 × N A
Therefore, the number of electrons present in 8.4 g of CO is approximately 4.2 times Avogadro's number of electrons.
Thus, the correct answer is option (D) 4.2 N A .
