Consider the following reaction:

$2H_{2}O(g)2H_2(g)+O_2(g)$

What is the rate expression for each substance in this equation?

Rate $=\frac{[H_{2}O]}{t}=\frac{[H_2]}{t}=\frac{[O_2]}{t}$

Rate $=\frac{2[H_{2}O]}{t}=\frac{2[H_2]}{t}=\frac{[O_2]}{t}$

Rate $=-\frac{1}{2}\frac{[H_{2}O]}{t}=\frac{1}{2}\frac{[H_2]}{t}=\frac{[O_2]}{t}$

Rate $=-\frac{2[H_{2}O]}{t}=\frac{2[H_2]}{t}=\frac{[O_2]}{t}$

Rate $=\frac{1}{2}\frac{[H_{2}O]}{t}=\frac{1}{2}\frac{[H_2]}{t}=\frac{[O_2]}{t}$