Exam 5: Thermochemistry: Energy Changes in Reactions

According to Coulomb's law, which ionic compound A-D has the largest electrostatic potential energy (i.e., largest in magnitude)? The size of the anion increases in the order F < Cl < Br < I.

For which reaction below does the enthalpy change under standard conditions correspond to a standard enthalpy of formation?

A food sample was burned in a bomb calorimeter containing 524 mL water. How much thermal energy was produced when the temperature of the water and the calorimeter rose from 20.0°C to 25.0°C? The metal calorimeter had a heat capacity of 725 J/°C without the water. The specific heat capacity of water is 4.184 J/(g °C).

Which statement A-D about a system and its surroundings is not correct?

What is the change in internal energy of a system when it loses 10 kJ of energy and 5,000 J of work is done on the system?

Which one of the following would you not expect to find in a table of enthalpies of formation.

In a Reuters news report dated February 3, 2010, President Obama is quoted as saying, "By 2022 we will more than double the amount of biofuels we produce to 36 billion gallons, which will decrease our dependence on foreign oil by hundreds of millions of barrels per year." Use the following information to determine the fraction of our projected 2022 total energy demand this target represents to assess its significance. (M = mega = 10⁶) U)S. projected annual energy demand in 2022: equivalent of 22 *10³ Mbarrels of oil Energy density of oil: 5.9 *10³ MJ/barrel Energy density of biofuels: 100 MJ/gal Mass density of petroleum: 900 g/L Mass density of biofuels: 800 g/L. 1 gal = 3.785 L.

If a mass of 100.0 g moves through a distance of 50.0 m with an acceleration of 25.0 m s^-2, How much work was necessary to move the mass? F = ma, where F is force, m is mass, and A is acceleration. (1 J = 1 kg m² s^-2)

Which of the following is an endothermic process for the system? In each case, the "system" is underlined.

What is the change in internal energy ( $\Delta$ E) when a system is heated with 35 J of energy while it does 15 J of work?

A student dissolving some ammonium nitrate (NH₄NO₃) in water notices that the beaker gets cooler as the solid dissolves. This is an example of ________

Which statement A-D about energy units is not correct?

Fuel density is ________

Which of the following objects will cool the fastest from the same initial temperature, assuming you had equal masses of each?

Given the standard enthalpies of formation for the following substances, determine the change in enthalpy for the combustion of 1.0 mol of butane. Substance \Delta \circ in / (g) -124.7 (g) -393.5 (g) -241.8

Using the following data for water, determine the energy required to melt 1.00 mole of ice (solid water) at its melting point. Boiling point 373 Melting point 273 Enthalpy of vaporization 2,260/ Enthalpy of fusion 334/ Specific heat capacity (solid) 2.11/(\cdot) Specific heat capacity (liquid) 4.18/(\cdot) Specific heat capacity (gas) 2.08/(\cdot)

Describe the difference between the change in the internal energy ( $\Delta$ E) of a system and the change in enthalpy ( $\Delta$ H). Begin your description with the definition of enthalpy change.

At a certain elevation, the boiling point of water is 98.5°C. How much energy is needed to heat 35.0 mL of water to the boiling point at this elevation if the water initially was at 23.4°C? (C_P = 75.38 J/(mol · °C), d = 1.00 g/mL)

Which of the following relationships among the heat capacity (C_P), specific heat capacity (c_s), and molar heat capacity (c_P) is not correct. I.C_P = c_s * mass of substance II.C_P = c_P * moles of substance III.c_s = C_P *mass of substance IV.c_P = c_s * molar mass V.c_s = c_P * molar mass

Benzoic acid is used to determine the heat capacity of bomb calorimeters because it can be obtained in pure form, and its energy of combustion is known very accurately (26.43 kJ/g). Determine the heat capacity of a calorimeter that had a temperature increase of 8.199°C when 2.500 g of benzoic acid was used.