Đáp án:
1. $Fe_xO_y+yH_2\to xFe+yH_2O$
2. $C_xH_y+\bigg(x+\dfrac y4\bigg)O_2\to xCO_2+\dfrac y2H_2O$
3. $Zn_xO_y+yCO\to xZn+ yCO_2$
4. $C_xH_yOz+\bigg(x+\dfrac y4-\dfrac z2\bigg)O_2\to xCO_2+\dfrac y2H_2O$
$5){C_n}{H_{2n}} + \dfrac{{3n}}{2}{O_2} \to nC{O_2} + n{H_2}O\\ 6){C_n}{H_{2n + 2}} + \bigg(\dfrac{{3n + 1}}{2}\bigg){O_2} \to nC{O_2} + (n + 1){H_2}O$