Question

1. If one mole of carbon atoms
weighs 12 grams, what is the
mass (in grams) of 1 atom of
carbon?​

Answer 1

Given :

• Weight of one mole of Carbon = 12 grams

To find :

Mass of 1 atom of Carbon

Formula used :

Number of atom = Number of moles × Avogadro's Number

Solution :

➝ Number of atom in 1 mole = 1 × Avogadro's Number

➝ Number of carbon atom Present = 6.02 × 10²³ atom

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Mass of 1 mole = 12 grams

this means,

➝ Mass of 6.02 × 10²³ atoms = 12 grams

$\sf \implies \: Mass \: of \: 1 \: atom \: = \: \dfrac{12}{6.02 \times {10}^{23} } \: g \: \\ \\ \sf \implies \: Mass \: of \: 1 \: atom \: = \:1.99 \times {10}^{ - 23} g$

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ANSWER :

Mass of 1 atom of carbon = 1.99 × 10⁻²³ grams

Answer 2

Explanation:

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$\text{\Large\underline{\red{Question:-}}}$

:$\Longrightarrow$ ● If one mole of carbon atoms weighs 12 grams, what is the mass (in grams) of 1 atom of

carbon?

$\text{\Large\underline{\orange{To\ find:-}}}$

$\sf To\ find = \begin{cases} \bf{●\ In\ this\ question\ we\ have\ to\ find\ the\ mass\ of\ 1\ atom\ of\ carbon.} \end{cases}$

$\text{\Large\underline{\green{Given:-}}}$

$\sf Given = \begin{cases} \bf{●\ Weight\ of\ one\ mole\ of\ carbon\ =\ 12g.} \\ \\ \bf{●\ 1\ mole\ of\ carbon\ contains\ 6.022\ ×\ 10²³\ atoms.} \end{cases}$

$\text{\Large\underline{\purple{Solution:-}}}$

● $\sf{Mass\ of\ one\ mole\ =\ 12g.}$

● $\sf{Mass\ of\ 6.022\ ×\ 10²³\ atoms\ of\ carbon\ weigh\ =\ 12g.}$

Here:-

● $\sf{Mass\ of_{(1\ atom)}\ =\ \dfrac{12}{6.022\ ×\ 10²³}}$

● $\sf{Mass\ of_{(1\ atom)}\ =\ 1.99\ ×\ 10^-²³\ g.}$

Hence:-

● $\sf{Mass\ of\ 1\ atom\ of\ carbon\ =\ 1.99\ ×\ 10^‐²³\ g.}$

$\text{\large\underline{\bf{More\ to\ know:-}}}$

Mole concept:-

● The amount of a substance which contains the same number of particles as the number of carbon atoms in 12g of C-12 isotope of carbon.

● The word mole was introduced by Wilhelm Ostwald (1896).

● Mass of 1 mole of a substance is called its molar mass.

Mole concept formulae:-

● $\sf{No.\ of\ moles\ =\ \dfrac{Given\ mass}{Molar\ mass}}$

$\sf{n\ =\ \dfrac{m}{M}}$

● $\sf{No.\ of\ moles\ =\ \dfrac{Given\ number\ of\ particles}{Avogardo\ number}}$

$\sf{n\ =\ \dfrac{N}{N_o}}$

● $\sf{No.\ of\ molecules\ =\ \dfrac{Given\ mass}{Molar\ mass}\ ×\ Avogardo\ number}$

$\sf{N\ =\ \dfrac{m}{M}\ ×\ N_{o}}$

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