Consider the following equation. 2H2 (g) + O2 (g) 2H2O (g); ΔH is negative. Which statement is true? The reaction is endothermic from left to right. Increased pressure would increase the rate of forming water vapor. Increased temperature would increase the rate of forming water vapor. The reactants are favored over the products.

Answer is: Increased pressure would increase the rate of forming water vapor.

According to Le Chatelier's Principle, the position of equilibrium moves to counteract the change, the position of equilibrium will move so that the concentration of products (water waper) of chemical reaction increase, if:

1) decrease temperature, because this is exothermic reaction (ΔH is negative).

2) increase concentration of reactants (oxygen and hydrogen).

3) increase pressure of the system, so reaction moves to direction where is less molecules.