What happens to the mass of reactants if a gas product escapes the reaction vessel?

When a gas product escapes from a reaction vessel, the overall mass of the reactants decreases. This is because the total mass of the system is based on the mass of the reactants that remain within the closed system. If a gas produced in the reaction escapes, it is no longer accounted for in the total mass measured in the vessel.

In a closed system, the mass of reactants should equal the mass of products (according to the law of conservation of mass) unless there's an escape of material — in this case, gas. Therefore, with the escape of a gas, the remaining mass within the reaction vessel is less than the initial mass of the reactants. This scenario illustrates a typical condition for reactions that involve gaseous byproducts, such as combustion or decomposition reactions, where the gas may be released into the atmosphere, thus reducing the mass tracked in the vessel.

The other options do not correctly represent the relationship between mass and gas release. Since mass can only be conserved if no materials leave the system, any escape will lead to a reduction in the measured mass.