Exam 6: Thermochemistry: Energy Flow and Chemical Change

The combustion of glucose (C₆H₁₂O₆) with oxygen gas produces carbon dioxide and water. This process releases 2803 kJ per mole of glucose. When 3.00 mol of oxygen react in this way with glucose, what is the energy release in kcal? (Hint: Write a balanced equation for the combustion process.)

$\Delta$ H does not depend on the path of a reaction, but $\Delta$ E does.

In which of the following processes is $\Delta$ H = $\Delta$ E ?

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A system initially has an internal energy E of 501 J. It undergoes a process during which it releases 111 J of heat energy to the surroundings, and does work of 222 J. What is the final energy of the system, in J?

A system delivers 225 J of heat to the surroundings while delivering 645 J of work. Calculate the change in the internal energy, $\Delta$ E, of the system.

Clearly state the thermodynamic standard state of A) an element or compound. B) a solute.

A piece of copper metal is initially at 100.0 $\degree$ C. It is dropped into a coffee cup calorimeter containing 50.0 g of water at a temperature of 20.0 $\degree$ C. After stirring, the final temperature of both copper and water is 25.0 $\degree$ C. Assuming no heat losses, and that the specific heat (capacity) of water is 4.18 J/(g ? K), what is the heat capacity of the copper in J/K?

For which one of the following reactions will $\Delta$ H be approximately (or exactly) equal to $\Delta$ E?

Which of the following is not a state function?

For all processes, both q and $\Delta$ E will have the same sign.

The standard state of a substance in aqueous solution is a 1 M solution.

Your favorite candy bar, Gummy Beakers, contains 1.2 *10⁶ J of energy while your favorite soft drink, Bolt, contains 6.7 *10⁵ J. If you eat two packs of Gummy Beakers a day and drink 3 cans of Bolt, what percent of your 2000 Calorie daily food intake is left for broccoli, beans, beef, etc.?

For a reaction in a sealed, rigid container, $\Delta$ H is always greater than $\Delta$ E.

A system contracts from an initial volume of 15.0 L to a final volume of 10.0 L under a constant external pressure of 0.800 atm. The value of w, in J, is:

Standard heats (enthalpies) of formation of compounds, $\Delta$ H $\degree$ _f, may be positive or negative.

A mass of 1.250 g of benzoic acid (C₇H₆O₂) was completely combusted in a bomb calorimeter. If the heat capacity of the calorimeter was 10.134 kJ/K and the heat of combustion of benzoic acid is -3226 kJ/mol, calculate (to three decimal places) the temperature increase that should have occurred in the apparatus.

Consider the equation $\Delta$ E = q + w. Explain fully the meaning of all three terms in the equation, and also the implied sign convention for q and w.

A system that does no work but which receives heat from the surroundings has:

When Karl Kaveman adds chilled grog to his new granite mug, he removes 10.9 kJ of energy from the mug. If it has a mass of 625 g and was at 25 $\degree$ C, what is its new temperature? Specific heat capacity of granite = 0.79 J/(g ? K)