Chapter 6: Thermochemistry: Energy Flow and Chemical ChangeD)The temperature of the solution is lower than of the barium hydroxide and water before mixing.E)When barium hydroxide dissolves in water, the system does work on the surroundings.Ans: B
Difficulty: M20.Two solutions (the system), each of 25.0 mL volume and at 25.0°C, are mixed in a beaker. A reaction occurs between them, and the temperature rises to 35.0°C. After the products have equilibrated with the surroundings, the temperature is again 25.0°C and the total volume is 50.0 mL. No gases are involved in the reaction. Which one of the following relationships concerning the change from initial to final states (both at 25.0°C) is correct?
E) w= 0
Difficulty: H21.A Snickers®candy bar contains 280 Calories, of which the fat content accounts for 120 Calories. What is the energy of the fat content, in kJ?
Difficulty: E22.Your favorite candy bar, Gummy Beakers, contains 1.2 106J of energy while your favorite soft drink, Bolt, contains 6.7 105J. If you eat two packs of Gummy Beakers aday and drink 3 cans of Bolt, what percent of your 2000 Calorie daily food intake is left for broccoli, beans, beef, etc.?
Difficulty: M23.Natural gas, or methane, is an important fuel. Combustion of one mole of methane releases 802.3 kilojoules of energy. How much energy does that represent in kilocalories?A)1.92 10–1kcalD)1.92 105kcalB)1.92 102kcalE)3.36 106kcalC)3.36 103 kcalAns: B
Difficulty: E24.Which of the following is not a state function?
Difficulty: EPage 88