The kinetic energy of a rolling billiard ball is given by KE = 1/2 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. Calculate q.

LP gas burns according to the exothermic reaction: C3H8( g) + 5 O2( g)¡3 CO2( g) + 4 H2O( g) ΔH °rxn = -2044 kJ What mass of LP gas is necessary to heat 2.50 L of water from room temperature (25.0 °C) to boiling (100.0 °C)? Assume that during heating, 15% of the heat emitted by the LP gas combustion goes to heat the water. The rest is lost as heat to the surroundings. (Assume a density of 1.00 g/mL for water.)

Use standard enthalpies of formation to calculate the standard change in enthalpy for the melting of ice. (The ΔH°_f for H₂O(s) is –291.8 kJ/mol.)

Use standard enthalpies of formation to calculate the standard change in enthalpy for the melting of ice. (The ΔH°_f for H₂O(s) is –291.8 kJ/mol.) Use this value to calculate the mass of ice required to cool 355 mL of a beverage from room temperature (25.0 °C) to 0.0 °C. Assume that the specific heat capacity and density of the beverage are the same as those of water.

Dry ice is solid carbon dioxide. Instead of melting, solid carbon dioxide sublimes according to the equation: CO₂(s) → CO₂(g) ◀ When carbon dioxide sublimes, the gaseous CO₂ is cold enough to cause water vapor in the air to condense, forming fog. When dry ice is added to warm water, heat from the water causes the dry ice to sublime more quickly. The evaporating carbon dioxide produces a dense fog often used to create special effects. In a simple dry ice fog machine, dry ice is added to warm water in a Styrofoam cooler. The dry ice produces fog until it evaporates away, or until the water gets too cold to sublime the dry ice quickly enough. Suppose that a small Styrofoam cooler holds 15.0 L of water heated to 85 °C. Use standard enthalpies of formation to calculate the change in enthalpy for dry ice sublimation, and calculate the mass of dry ice that should be added to the water so that the dry ice completely sublimes away when the water reaches 25 °C. Assume no heat loss to the surroundings. (The ΔH°_f for CO₂(s) is –427.4 kJ/mol.)

A 25.5-g aluminum block is warmed to 65.4 °C and plunged into an insulated beaker containing 55.2 g water initially at 22.2 °C. The aluminum and the water are allowed to come to thermal equilibrium. Assuming that no heat is lost, what is the final temperature of the water and aluminum?

If 50.0 mL of ethanol (density = 0.789 g/mL) initially at 7.0 °C is mixed with 50.0 mL of water (density = 1.0 g/mL) initially at 28.4 °C in an insulated beaker, and assuming that no heat is lost, what is the final temperature of the mixture?

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? 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.]

Palmitic acid (C₁₆H₃₂O₂) is a dietary fat found in beef and butter. The caloric content of palmitic acid is typical of fats in general. 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.]

Hydrogen and methanol have both been proposed as alternatives to hydrocarbon fuels. Which fuel contains the most energy in the least mass?

Hydrogen and methanol have both been proposed as alternatives to hydrocarbon fuels. How does the energy of these fuels compare to that of octane (C₈H₁₈)? 

Under certain nonstandard conditions, oxidation by O₂(g) of 1 mol of SO₂(g) to SO₃(g) absorbs 89.5 kJ. The enthalpy of formation of SO₃(g) is –204.2 kJ under these conditions. Find the enthalpy of formation of SO₂(g).

A mixture of 2.0 mol of H₂(g) and 1.0 mol of O₂(g) is placed in a sealed evacuated container made of a perfect insulating material at 25 °C. The mixture is ignited with a spark and reacts to form liquid water. Determine the temperature of the water.

A 20.0-L volume of an ideal gas in a cylinder with a piston is at a pressure of 3.0 atm. Enough weight is suddenly removed from the piston to lower the external pressure to 1.5 atm. The gas then expands at constant temperature until its pressure is 1.5 atm. Find w.

When 10.00 g of phosphorus is burned in O₂(g) to form P₄O₁₀(s), enough heat is generated to raise the temperature of 2950 g of water from 18.0 °C to 38.0 °C. Calculate the enthalpy of formation of P₄O₁₀(s) under these conditions.

The ΔH for the oxidation of sulfur in the gas phase to SO₃ is –204 kJ/mol and for the oxidation of SO₂ to SO₃ is 89.5 kJ/mol. Find the enthalpy of formation of SO₂ under these conditions.

The ΔH°_f of TiI₃(s) is –328 kJ/mol and the ΔH ° for the reaction 2 Ti(s) + 3 I₂(g) → 2 TiI₃(s) is –839 kJ. Calculate the ΔH of sublimation of I₂(s), which is a solid at 25 °C.

A gaseous fuel mixture contains 25.3% methane (CH₄), 38.2% ethane (C₂H₆), and the rest propane (C₃H₈) by volume. When the fuel mixture contained in a 1.55 L tank, stored at 755 mmHg and 298 K, undergoes complete combustion, how much heat is emitted? (Assume that the water produced by the combustion is in the gaseous state.)

A gaseous fuel mixture stored at 745 mmHg and 298 K contains only methane (CH₄) and propane (C₃H₈). When 11.7 L of this fuel mixture is burned, it produces 769 kJ of heat. What is the mole fraction of methane in the mixture? (Assume that the water produced by the combustion is in the gaseous state.)