Chapter 7

In which state(s) of matter are atoms a. closest together? b. farthest apart? c. filling the container? d. fixed in position relative to one another? e. moving past one another? f. taking on the shape of the container?

Which of the following statements are true? Correct any false statements. a. All substances exist as a liquid at room temperature and pressure. b. Water changes from liquid to solid at \(32^{\circ} \mathrm{C}\). c. All substances can exist as solids, liquids, or gases.

Which state of matter is most compressible?

Use online resources to find the boiling point of ethanol and dimethyl ether. Which one is higher? Why?

Describe the relationship between boiling point and altitude.

What phase change is described by each term? Is the process endothermic or exothermic? a. sublimation b. vaporization C. fusion d. deposition

List two phase changes that consume energy.

List two phase changes that release energy.

Calculate the quantity of heat that is absorbed or released during each process. a. \(655 \mathrm{~g}\) of water vapor condenses at \(100^{\circ} \mathrm{C}\) b. \(8.20 \mathrm{~kg}\) of water is frozen c. \(40.0 \mathrm{~mL}\) of ethanol is vaporized. The density of ethanol is \(0.789 \mathrm{~g} / \mathrm{mL}\). d. \(25.0 \mathrm{~mL}\) of ethanol condenses. The density of ethanol is \(0.789 \mathrm{~g} / \mathrm{mL}\).

What is \(\Delta H_{v a p}\) for benzene \(\left(\mathrm{C}_{6} \mathrm{H}_{6}\right)\) if \(7.88 \mathrm{~kJ}\) of energy is needed to vaporize \(20.0 \mathrm{~g}\) of benzene?

How are gases different from liquids and solids in terms of the distance between the particles?

Under what conditions do gases exhibit the most ideal behavior?

\text { Under what conditions do gases exhibit the most ideal behavior? }

What is an elastic collision?

Perform the indicated conversions for the following pressure measurements. a. \(1.721\) atm to \(\mathrm{mmHg}\) b. 559 torr to \(\mathrm{kPa}\) c. \(91.1 \mathrm{kPa}\) to atm d. \(2320 \mathrm{mmHg}\) to atm

a. A typical barometric pressure in Redding, California, is about \(755 \mathrm{mmHg}\). Calculate this pressure in atm and kPa. b. A typical barometric pressure in Denver, Colorado, is \(615 \mathrm{mmHg}\). What is this pressure in atmospheres and kilopascals?

How does the average kinetic energy of an air sample near a campfire compare to the average kinetic energy of a sample of air that is far away from it?

What units must temperature be in for gas law calculations?

Based on \(\mathrm{R}=0.08206 \frac{\text { Latm }}{\mathrm{molK}}\), what units should be used in ideal gas law calculations?

A \(1.00\) mol sample of gas is at \(300 \mathrm{~K}\) and \(4.11\) atm. What is the volume of the gas under these conditions?

What is the pressure in a \(2.5 \mathrm{~L}\) container with \(2.5\) moles of gas at \(293 \mathrm{~K}\) ?

How many moles of carbon monoxide, CO, are in an 11.2-L sample at 744 torr at \(55^{\circ} \mathrm{C}\) ?

A weather balloon contains \(8.80\) moles of helium at a pressure of \(0.992\) atm and a temperature of \(25^{\circ} \mathrm{C}\) at ground level. What is the volume of the balloon under these conditions?

A balloon inflated with three breaths of air has a volume of \(1.7 \mathrm{~L}\). At the same temperature and pressure, what is the volume of the balloon if five more same-sized breaths are added to the balloon?

The volume of an automobile air bag was \(66.8 \mathrm{~L}\) when inflated at \(25^{\circ} \mathrm{C}\) with \(77.8 \mathrm{~g}\) of nitrogen \(\left(\mathrm{N}_{2}\right)\) gas. What was the pressure in the bag in \(\mathrm{kPa}\) ?

How many moles of gaseous boron trifluoride, \(\mathrm{BF}_{3}\), are contained in a 4.3410-L bulb at \(788.0 \mathrm{~K}\) if the pressure is \(1.220\) atm? How many grams of \(\mathrm{BF}_{3}\) ?

How is the combined gas law is simplified for each set of conditions? a. constant \(\mathrm{V}\) and \(\mathrm{n}\) b. constant \(n\) c. constant \(\mathrm{P}\) and \(\mathrm{V}\) d. constant \(\mathrm{T}\) and \(\mathrm{n}\) e. constant \(\mathrm{V}\) and \(\mathrm{T}\) f. constant \(\mathrm{P}\) and \(\mathrm{n}\) g. constant T

A nitrogen sample has a pressure of \(0.56\) atm with a volume of \(2.0 \mathrm{~L}\). What is the final pressure if the volume is compressed to a volume of \(0.75 \mathrm{~L}\) ? Assume constant moles and temperature.

A 2.50-L volume of hydrogen measured at \(-196^{\circ} \mathrm{C}\) is warmed to \(100{ }^{\circ} \mathrm{C}\). Calculate the volume of the gas at the higher temperature, assuming no change in pressure.

A high altitude balloon is filled with \(1.41 \times 10^{4} \mathrm{~L}\) of hydrogen at a temperature of \(21^{\circ} \mathrm{C}\) and a pressure of 745 torr. What is the volume of the balloon at a height of \(20 \mathrm{~km}\), where the temperature is \(-48^{\circ} \mathrm{C}\) and the pressure is \(63.1\) torr?

A cylinder of medical oxygen has a volume of \(35.4 \mathrm{~L}\), and contains \(\mathrm{O}_{2}\) at a pressure of 151 atm and a temperature of \(25^{\circ} \mathrm{C}\). What volume of \(\mathrm{O}_{2}\) does this correspond to at normal body conditions, that is, \(1 \mathrm{~atm}\) and \(37^{\circ} \mathrm{C}\) ?

A \(0.50 \mathrm{~L}\) container of helium expands to \(1.50 \mathrm{~L}\). By what factor does the pressure change? Assume constant moles and temperature.

A sample of oxygen gas has an initial pressure and volume of \(1.0 \mathrm{~L}\) and \(1.0\) atm. What is the final pressure if the volume is compressed to \(0.50 \mathrm{~L}\) ? Assume constant moles and temperature.

A sample of gas has a volume of \(2.75 \mathrm{~L}\) at a temperature of \(100 \mathrm{~K}\). What is the volume of the gas when the temperature increases to \(200 \mathrm{~K}\) ? Assume constant pressure and moles.

What is the final volume of a gas that was originally at \(0.75 \mathrm{~L}\) at \(25^{\circ} \mathrm{C}\) and a final temperature of \(50^{\circ} \mathrm{C}\) ? Assume constant pressure and moles.

A sample of nitrogen is at \(45^{\circ} \mathrm{C}\) with a volume of \(2.5 \mathrm{~L}\). What is the final temperature in \({ }^{\circ} \mathrm{C}\) if the volume is compressed to \(1.4\) L? Assume constant pressure and moles.

A \(2.00\) mole sample of gas is in a \(3.50 \mathrm{~L}\) container. What happens to the volume when an additional \(0.75\) moles of gas is added? Assume pressure and temperature are constant.

A \(1.85\) mole sample of helium has a volume of \(2.00 \mathrm{~L}\). Additional helium is added at constant pressure and temperature until the volume is \(3.25 \mathrm{~L}\). What is the total moles of helium present in the sample? What mass of helium was added?

If the temperature of a fixed amount of a gas is doubled at constant volume, what happens to the pressure?

If the volume of a fixed amount of a gas is tripled at constant temperature, what happens to the pressure?

Describe the solution, solvent, and solute.

How do solutions differ from compounds? Are solutions heterogeneous or homogeneous mixtures?

When \(\mathrm{KNO}_{3}\) is dissolved in water, the resulting solution is significantly colder than the water was originally. Is the dissolution of \(\mathrm{KNO}_{3}\) an endothermic or an exothermic process?

What are the differences between strong, weak and non-electrolytes.

Write dissociation equations for the following strong electrolytes. a. \(\mathrm{NaCl}(s)\) b. \(\mathrm{CoCl}_{3}(s)\) c. \(\mathrm{Li}_{2} \mathrm{~S}(\mathrm{~s})\) d. \(\mathrm{MgBr}_{2}(s)\) e. \(\mathrm{CaF}_{2}(s)\)

Based on the given information, identify each as a strong, weak, or non- electrolyte. a. \(\mathrm{C}_{6} \mathrm{H}_{12} \mathrm{O}_{6}(s) \rightarrow \mathrm{C}_{6} \mathrm{H}_{12} \mathrm{O}_{6}(a q)\) b. \(\mathrm{NaCl}\) is added to water and the conductivity increases dramatically. c. \(1.5\) moles of \(\mathrm{HCl}\) are added to a container of water. The resulting solution has \(1.5\) moles of \(\mathrm{H}^{+}\) ions and \(1.5\) moles of \(\mathrm{Cl}^{-}\) ions. d. Acetic acid (CH \(_{3}\) COOH) partially dissociates in water. e. An HCN solution contains \(0.50\) moles of HCN molecules and \(0.05\) moles of \(\mathrm{H}^{+}\) ions and \(0.05\) moles of \(\mathrm{Cl}^{-}\) ions. f. Acetone is added to water and the conductivity does not change.

How big are the particles in a colloid compared to those of a suspension and a solution?

What is the Tyndall effect? Why don't solutions demonstrate the Tyndall effect?

Explain the difference between the dispersed phase and the dispersing medium of a colloid.

Identify each of the following descriptions or examples as being representative of a solution, suspension, or colloid. More than one answer may apply. a. dispersed particles can be filtered out b. heterogeneous c. particles are not visible to the unaided eye d. paint e. lemonade with no pulp f. particle size larger than \(1 \mathrm{~nm}\) g. milk h. particles do not settle upon standing i. fog