Starting at the same temperature, tea and coffee remain hot longer in a thermal flask than chicken noodle soup. Explain.

The specific heat capacities of the metals nickel, zinc, rhodium, tungsten, gold, and uranium at 25°C are 0.444, 0.388, 0.243, 0.132, 0.129, and 0.116 J K^-1 g^-1, respectively. Calculate the molar heat capacities of these six metals. Note how closely the molar heat capacities for these metals, which were selected at random, cluster about a value of 25 J K^-1 mol ^-1. The rule of Dulong and Petit states that the molar heat capacities of the metallic elements are approximately 25 J K^-1 mol^-1.

Where in an angiosperm would you find a megasporangium? ( A ) in the style of a flower ( B ) enclosed in the stigma of a flower ( C ) within an ovule contained within an ovary of a flower ( D ) packed into pollen sacs within the anthers found on stamen

Where in an angiosperm would you find a megasporangium? ( A ) in the style of a flower ( B ) enclosed in the stigma of a flower ( C ) within an ovule contained within an ovary of a flower ( D ) packed into pollen sacs within the anthers found on stamen

A quantity of $0.020$ mole of a gas initially at $0.050 \mathrm{~L}$ and $20^{\circ} \mathrm{C}$ undergoes a constant-temperature expansion until its volume is $0.50 \mathrm{~L}$. Calculate the work done (in joules) by the gas if it expands
If the gas in (b) is allowed to expand unchecked until its pressure is equal to the external pressure, what would its final volume be before it stopped expanding, and what would be the work done?

A quantity of $0.020$ mole of a gas initially at $0.050 \mathrm{~L}$ and $20^{\circ} \mathrm{C}$ undergoes a constant-temperature expansion until its volume is $0.50 \mathrm{~L}$. Calculate the work done (in joules) by the gas if it expands
against a constant pressure of $0.20$ bar.

A quantity of $0.020$ mole of a gas initially at $0.050 \mathrm{~L}$ and $20^{\circ} \mathrm{C}$ undergoes a constant-temperature expansion until its volume is $0.50 \mathrm{~L}$. Calculate the work done (in joules) by the gas if it expands
against a vacuum.

The molar enthalpy of vaporization of a liquid $\left(\Delta H_{\text {vap }}\right)$ is the energy required to vaporize $1.00 \mathrm{~mol}$ of the liquid. In one experiment, $60.0 \mathrm{~g}$ of liquid nitrogen (boiling point $-196^{\circ} \mathrm{C}$ ) is poured into a Styrofoam cup containing $2.00 \times 10^2 \mathrm{~g}$ of water at $55.3^{\circ} \mathrm{C}$. Calculate the molar enthalpy of vaporization of liquid nitrogen if the final temperature of the water is $41.0^{\circ} \mathrm{C}$.

Producer gas (carbon monoxide) is prepared by passing air over red-hot coke:

$$\mathrm{C}(\mathrm{s})+\frac{1}{2} \mathrm{O}_2(\mathrm{~g}) \longrightarrow \mathrm{CO}(\mathrm{g})$$

Water gas (a mixture of carbon monoxide and hydrogen) is prepared by passing steam over redhot coke:

$$\mathrm{C}(\mathrm{s})+\mathrm{H}_2 \mathrm{O}(\mathrm{g}) \longrightarrow \mathrm{CO}(\mathrm{g})+\mathrm{H}_2(\mathrm{~g})$$

For many years, both producer gas and water gas were used as fuels in industry and for domestic cooking. The large-scale preparation of these gases was carried out alternately, that is, first producer gas, then water gas, and so on. Using thermochemical reasoning, explain why this procedure was chosen.

A 1.00-mole sample of ammonia at $14.0$ bar and $25^{\circ} \mathrm{C}$ in a cylinder fitted with a movable piston expands against a constant external pressure of $1.00$ bar. At equilibrium, the pressure and volume of the gas are $1.00$ bar and $23.5 \mathrm{~L}$, respectively.
Calculate $q, w$, and $\Delta U$ for the process. The specific heat capacity of ammonia is $0.0258 \mathrm{~J} \mathrm{~g}^{\circ} \mathrm{C}^{-1}$.

A 1.00-mole sample of ammonia at $14.0$ bar and $25^{\circ} \mathrm{C}$ in a cylinder fitted with a movable piston expands against a constant external pressure of $1.00$ bar. At equilibrium, the pressure and volume of the gas are $1.00$ bar and $23.5 \mathrm{~L}$, respectively.
Calculate the final temperature of the sample.

Show that the work required for the reversible and isothermal expansion of $n$ moles of a van der Waals gas (Equation $5.42$ ) from an initial volume $V_1$ to a final volume $V_2$ is given by

$$w=n R T \ln \frac{V_1-n b}{V_2-n b}+a n^2\left(\frac{1}{V_1}-\frac{1}{V_2}\right)$$

The combustion of what volume of ethane $\left(\mathrm{C}_2 \mathrm{H}_6\right)$, measured at $23.0^{\circ} \mathrm{C}$ and $752 \mathrm{~mm} \mathrm{Hg}$, would be required to heat $855 \mathrm{~g}$ of water from $25.0^{\circ} \mathrm{C}$ to $98.0^{\circ} \mathrm{C}$ ?

Calculate the work done (in joules) when 1.0 mole of water vaporizes at 1.0 atm and 100$\degree$C. Assume ideal gas behavior and that the volume of liquid water is negligible compared with that of steam at 100$\degree$C.