Mr. Gill is attempting to grow some new flowers at home. He knows that flowers and plants alike produce energy through photosynthesis (chemical reaction below). Using what you know about Le Chatelier’s Principle, provide Mr. Gill with one adjustment he could make to increase the rate at which his flowers are growing. Explain why you chose this adjustment. 6CO2 + 6H2O ←→ C6H12O6 + 6O2

Write a chemical equation for each process and classify each as reactant-favored or product-favored. (a) A puddle of water evaporates on a summer day. (b) Silicon dioxide (sand) decomposes to the elements Silicon and oxygen. (c) Paper, which is mainly cellulose (C6H10O5)n, bums at a temperature of 451 F. (d) A pinch of sugar dissolves in water at room temperature.

Indicate which of the following processes are reversible. (a) Nitrogen gas expands into a vacuum. (b) Dry ice, CO2(s), sublimes at 25 C and 1.0 atm. (c) Energy as heat is added to a mixture of ice and water at 0 C, causing some of the ice to melt. (d) Methanol and ethanol mix forming a homogeneous solution.

When a mixture of hydrogen and bromine is maintained at normal atmospheric pressure and heated above 200. °C in a closed container, the hydrogen and bromine react to form hydrogen bromide and a gas-phase equilibrium is established. Write a balanced chemical equation for the equilibrium reaction. Use bond enthalpies from Table 6.2 ( Sec. 6-6b) to estimate the enthalpy change for the reaction. Based on your answers to parts (a) and (b), which is more important in determining the position of this equilibrium, the entropy effect or the energy effect? In which direction will the equilibrium shift as the temperature increases above 200. °C? Explain. Suppose that the pressure were increased to triple its initial value. In which direction would the equilibrium shift? Why is the equilibrium not established at room temperature?