ms = 10 g , c% = 36,5% , c% = mdx100/ms
=> md= msxc% /100 = 10x36,5/100 = 3,65 g HCl
...............3,65 g......................... n moli
Zn + 2HCl => ZnCl2 + H2
............... 2 x36,5 ..................... 1
=> n = 3,65/2x36,5 = 0,05 moli H2 au rezultat din reactia Zn cu HCl
a moli ... n moli
CuO + H2 => Cu + H2O
1..............1
=> a = nx1/1 = 0,05x1/1 = 0,05 moli CuO
nr moli = masa / M.moleculara, M.moleculara CuO = 64+16 = 70 g/mol
=> m = 0,05x70 = 3,5 g CuO