The kinetic energy of a rolling billiard ball is given by KE = 12 mv2. Suppose a 0.17-kg billiard ball is rolling down a pool table with an initial speed of 4.5 m>s. As it travels, it loses some of its energy as heat. The ball slows down to 3.8 m>s and then collides head-on with a second billiard ball of equal mass. The first billiard ball completely stops, and the second one rolls away with a velocity of 3.8 m>s. Assume the first billiard ball is the system and calculate w, q, and E for the process.
Palmitic acid (C16H32O2) is a dietary fat found in beef and butter. The caloric content of palmitic acid is typical of fats in general. Write a balanced equation for the complete combustion of palmitic acid and calculate the standard enthalpy of combustion. What is the caloric content of palmitic acid in Cal >g? Do the same calculation for table sugar (sucrose, C12H22O11). Which dietary substance (sugar or fat) contains more Calories per gram? The standard enthalpy of formation of palmitic acid is -208 kJ>mol, and that of sucrose is -2226.1 kJ>mol. (Use H2O(l) in the balanced chemical equations because the metabolism of these compounds produces liquid water.)
A typical frostless refrigerator uses 655 kWh of energy per year in the form of electricity. Suppose that all of this electricity is generated at a power plant that burns coal containing 3.2% sulfur by mass and that all of the sulfur is emitted as SO2 when the coal is burned. If all of the SO2 goes on to react with rainwater to form H2SO4, what mass of H2SO4 does the annual operation of the refrigerator produce? (Hint: Assume that the remaining percentage of the coal is carbon and begin by calculating Hrxn for the combustion of carbon.)
Combustion of natural gas (primarily methane) occurs in most household heaters. The heat given off in this reaction is used to raise the temperature of the air in the house. Assuming that all the energy given off in the reaction goes to heating up only the air in the house, determine the mass of methane required to heat the air in a house by 10.0 C. Assume that the house dimensions are 30.0 m * 30.0 m * 3.0 m; specific heat capacity of air is 30 J>K # mol; and 1.00 mol of air occupies 22.4 L for all temperatures concerned.