Q9 / 160 · TS EAMCET 2020 (09 Sep Shift 2) · Chemistry

How many grams of $\mathrm{Cu}\left(\mathrm{NO}_3\right)_2$ is needed to get 1 gram of copper? $($ Atomic mass, $\mathrm{Cu}=63.5, \mathrm{~N}=14, \mathrm{O}=16$ )

  • A
    $1.00$
  • B
    $2.00$
  • C
    $1.95$
  • Correct answer
    D
    $2.95$

Solution

In $\mathrm{Cu}\left(\mathrm{NO}_3\right)_2$ $\begin{gathered}\text { Given, atomic mass of } \mathrm{Cu}=63.5 \times \frac{1}{5}=63.5 \\ \mathrm{~N}=14 \times 2=28 \\ \mathrm{O}=16 \times 6=96 \\ \text { Total mass }=63.5+28+96=187.5 \mathrm{~g}\end{gathered}$ $\because 63.5$ of copper will get by $=187.5 \mathrm{~g}$ of $\mathrm{Cu}\left(\mathrm{NO}_3\right)_2$ $\therefore 1 \mathrm{~g}$ of copper will get by $=\frac{187}{63.5}=2.95 \mathrm{~g}$ Hence, option (d) is the correct answer.

Hence, the correct answer is option: 'D'.

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