Complete combustion of 3g of ethane gives x $\times$ 1022 molecules of water. The value of x is __________. (Round off to the Nearest Integer). [Use : NA = 6.023 $\times$ 1023; Atomic masses in u : C : 12.0; O : 16.0; H : 1.0]
Answer (integer)
18
Solution
$${C_2}{H_6} + {7 \over 2}{O_2}\buildrel {} \over
\longrightarrow 2C{O_{\,2}} + 3{H_2}O$$<br><br>Here, ${C_2}{H_6} = 3gm = {3 \over {30}} = 0.1$ mol<br><br>From 1 mol C<sub>2</sub>H<sub>6</sub> we get 3 mol H<sub>2</sub>O<br><br>$\therefore$ From 0.1 mol C<sub>2</sub>H<sub>6</sub> we get = 3 $\times$ 0.1 mol H<sub>2</sub>O<br><br>$\therefore$ Moles of H<sub>2</sub>O = 0.3<br><br>= 0.3 $\times$ 6.023 $\times$ 10<sup>23</sup> molecules<br><br>= 1.8069 $\times$ 10<sup>23</sup> molecules<br><br>= 18.069 $\times$ 10<sup>22</sup> molecules
About this question
Subject: Chemistry · Chapter: Some Basic Concepts of Chemistry · Topic: Mole Concept
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