Final answer:
An increase in temperature shifts the equilibrium to favor the endothermic direction while a decrease in volume increases pressure, shifting the balance towards fewer gas moles. For the provided reactions, temperature and volume changes will alter the equilibrium position as predicted by Le Chatelier's principle, affecting the concentrations of reactants and products accordingly.
Step-by-step explanation:
When considering how changes in temperature and volume of the reaction vessel affect chemical equilibria, Le Chatelier's principle provides guidance. It states that if a dynamic equilibrium is disturbed by changing the conditions, the position of equilibrium moves to counteract the change.
- Increase in temperature: For endothermic reactions (positive ΔH), increasing temperature will shift the equilibrium to the right to absorb the added heat. Conversely, for exothermic reactions (negative ΔH), an increase in temperature will shift the equilibrium to the left, as the system tries to release heat.
- Decrease in volume: Decreasing the volume of the reaction vessel increases the pressure. For reactions involving gases, the equilibrium will shift towards the side with fewer moles of gas to reduce pressure.
Applying this to the reactions you provided:
- For the reaction 2NH3(g) → N2(g) + 3H2(g) (endothermic), increasing temperature favors the formation of N2 and H2, and decreasing volume favors the formation of NH3 due to a smaller number of gas molecules on that side of the equation.
- In the case of N2(g) + O2(g) → 2NO(g) (endothermic), raising the temperature shifts the equilibrium to the right (producing more NO), while reducing volume will have no net effect as the number of gas molecules does not change.
- For 2O3(g) → 3O2(g) (exothermic), higher temperatures will shift the equilibrium to the left (forming more O3), whereas decreasing the volume favors the side with fewer gas molecules, which is the formation of O2.
- Lastly, the reaction CaO(s) + CO2(g) → CaCO3(s) (exothermic), will be shifted to the left with an increase in temperature (producing more CaO and CO2), and changes in volume will not significantly affect the solids but an increase in pressure will favor the production of CaCO3 because there are fewer moles of gas on that side.