Question

Calculate the weight in grams of 22×10²² molecules of copper sulphate. Take Avogadro’s number as 6×10²³

Answer 1

$\color{darkblue}\underline{\underline{\sf Given-}}$

• Number of molecule of copper sulphate = 22 × 10²²
• Avogadro number ${\sf (N_A)}$ = 6×10²³

$\color{darkblue}\underline{\underline{\sf To \: Find-}}$

• Mass of copper sulphate ${\sf CuSO_4}$

As we know

$\color{red}\blacksquare\boxed{\sf Number\:of\: molecule=mole×molecular\:weight}$

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Molecular Weight of ${\sf CuSO_4=63+32+(4×16)}$

$\color{orange}\implies{\sf 159 }$

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$\implies{\sf 22×10^{22}=n×6×10^{23}}$

$\implies{\sf n=\dfrac{22×10^{22}}{6×10^{23}}}$

$\implies{\sf n= 0.36\:mole}$

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Now ,

$\color{red}\blacksquare\boxed{\sf Mole(n)=\dfrac{Mass}{Molecular\:Mass}}$

$\implies{\sf 0.36=\dfrac{Mass}{127}}$

$\implies{\sf Mass=0.36×159 }$

$\color{red}\implies{\sf Mass=54.2g}$

$\color{darkblue}\underline{\underline{\sf Answer-}}$

Weight of ${\sf CuSO_4}$ will be $\color{red}{\sf 54.2g}$.