Answer to Question #142838 in General Chemistry for Tara

Question

when 286g CU reacts with an excess of HNO3 what mass of NO is f

Answer 1

$\begin{aligned} \small 3Cu_{(s)} + 8HNO_{3(aq)} \to 2NO_{(g)} + 3Cu(NO_3)_{2(aq)} + 4H_2O_{(l)} \end{aligned}$

from the reaction above,

3 moles of Cu produces 2 moles of NO.

286g of Cu = 4.5 moles of Cu.

4.5 moles of Cu produces $(\frac{4.5×2}{3}=)$ 3 moles of NO

3 moles of NO = 3(14+16) = 3(30) = 90g.

$\therefore$ when 286g CU reacts with an excess of HNO3, 90g mass of NO is produced.