# Which is the valid observation for the reaction...? 3O_2(g)rarr2O_3(g)

## $\text{1. The mass of the products increase.}$ $\text{2. This is an exothermic reaction.}$ $\text{3. The pressure of the reaction mixture should DECREASE.}$ $\text{4. The pressure of the reaction mixture should INCREASE.}$

Oct 17, 2016

$\text{Option 3}$ is the best answer.

#### Explanation:

All chemical reactions conserve mass. If you start with 10 g of reactant, from all sources, at MOST, you can get 10 g of reactant. In practice, you are not even going to get that.

The equation clearly shows that the number of gaseous molecules is reduced; nevertheless, mass is conserved:

$3 {O}_{2} \left(g\right) \rightarrow 2 {O}_{3} \left(g\right)$

And thus pressure is reduced due to the decrease in the number of gaseous particles.

$\text{Option 3}$ certainly describes the scenario.