Chemistry

45. For each of the following pairs of gas properties, describe the relationship between the properties, describe a simple system that could be used to demonstrate the relationship, and explain the reason for the relationship:

(a) volume and pressure when number of gas particles and temperature are constant,

(b) pressure and temperature when volume and the number of gas particles are constant,

(c) volume and temperature when pressure and the number of gas particles are

constant,

(d) the number of gas particles and pressure when volume and temperature are constant, and (e) the number of gas particles and volume when pressure and temperature are constant.

56. Ethylene oxide is produced from the reaction of ethylene and oxygen at 270-290 °C and 8-20 atm. In order to prevent potentially dangerous pressure buildups, the container in which this reaction takes place has a safety valve set to release gas when the pressure reaches 25 atm. If a 15-m3 reaction vessel contains 7.8 × 103 moles of gas, at what temperature will the pressure reach 25 atm?

(There are 103 L per m3.)

84. The hydrogen gas used to make ammonia can be made from small hydrocarbons such as methane in the so-called steam-reforming process, run at high temperature and pressure.

a. If 3.2 atm of methane at 21 °C are introduced into a container, to what temperature must the gas be heated to increase the pressure to 12 atm?

b. If 4.0 × 103 L of methane gas at 21 °C is heated and allowed to expand at a constant pressure, what will the volume become in m3 when the temperature reaches 815 °C?

c. What volume of methane gas at 21 °C and 1.1 atm must be compressed to yield 1.5 × 104 L of methane gas at 12 atm and 815 °C?

90. The hydrogen gas needed to make ammonia, hydrogen chloride gas, and methanol can be obtained from small hydrocarbons such as methane or propane through the steam-reforming process, conducted at 41 atm and 760-980 °C. If 2.7 × 107 L of C3H8(g) at 810 °C and 8.0 atm react in the first step of the process, shown below, what is the maximum volume in liters of CO(g) at STP that can form?

C3H8 + 3H2O → 3CO + 7H2 3CO + 3H2O → 3CO2 + 3H2

103. The atmosphere of Venus contains carbon dioxide and nitrogen gases. At the planet’s surface, the temperature is about 730 K, the total atmospheric pressure is 98 atm, and the partial pressure of carbon dioxide is 94 atm. If scientists wanted to collect 10.0 moles of gas from the surface of Venus, what volume of gas should they collect?

41. Acetone, CH3COCH3, is a laboratory solvent that is also commonly used as a

nail polish remover.

a. Describe the submicroscopic events taking place at the surface of liquid

acetone when it evaporates.

b. Do all of the acetone molecules moving away from the surface of the liquid

escape? If not, why not? What three criteria must be met for a molecule to

escape from the surface of the liquid and move into the gas phase?

c. If you spill some nail polish remover on your hand, the spot will soon feel

cold. Why?

d. If you spill some acetone on a lab bench, it evaporates much faster than the

same amount of acetone in a test tube. Why?

e. If you spill acetone on a hot plate in the laboratory, it evaporates much

more quickly than the same amount of acetone spilled on the cooler lab

bench. Why?

50. Butane is a gas at room temperature and pressure, but the butane found in some

cigarette lighters is a liquid. How can this be?

55. Classify each of the following bonds as nonpolar covalent, polar covalent, or ionic. If a bond is polar covalent, identify the atom that has the partial negative charge and the atom that has the partial positive charge. If a bond is ionic, identify the ion that has the negative charge and the ion that has the positive charge.

a. N−O d. H−I g. Se−I j. F−P

b. Al−Cl e. Br−Cl h. N−Sr

c. Cl−N f. Cl−S

i. O−F

37. Would the following combinations be expected to be soluble or insoluble?

a. polar solute and nonpolar solvent

b. nonpolar solute and nonpolar solvent

c. ionic solute and hexane

d. molecular solute with small molecules and water

e. hydrocarbon solute and hexane

41. Predict whether each of the following is soluble in water or not.

a. potassium hydrogen sulfate, KHSO4 (used in wine making)

b. the polar molecular compound propylene glycol, CH3CH(OH)CH2OH (used in some antifreezes)

c. benzene, C6H6 (use to produce many organic compounds)

55. You throw a backyard party that resembles your idea of a big Texas barbecue. The guests get more food than they could possibly eat, including a big juicy steak in the center of each plate. Describe how soap or detergent can help you clean the greasy plates you’re left with when your guests go home, referring to the interactions between particles and the corresponding changes that take place on the submicroscopic level.

62. Some of the minerals found in rocks dissolve in water as it flows over the rocks. Would these minerals dissolve more quickly

a. at the bottom of a waterfall or in a still pond? Why?

b. in a cold mountain stream or in the warmer water downstream? Why?

c. over large rocks or over sand composed of the same material? Why?

64. Solutions are called dilute when the concentration of the solute in solution is relatively low and concentrated when the concentration is relatively high. Can a solution be both dilute and saturated? Explain your answer

66. The soft drinks sold at county fairs are often dispensed from large pressurized containers that contain carbon dioxide gas above the liquid at a partial pressure of about 4 atm, compared to carbon dioxide’s normal partial pressure of 0.00035 atm in the air at sea level.

a. Describe the reversible change that takes place inside one of these soft drink containers when the pressure of CO2 above the liquid is first brought from 0.00035 atm to 4 atm. Explain why this system comes to a dynamic equilibrium in which there is no net change in the amount of gas above the liquid or the amount of gas dissolved in the liquid.

b. Explain why an increase in the partial pressure of CO2 over a liquid leads to an increase in the solubility of the gas in the liquid.

75. Surfactants are an important class of compounds. As described in the textbook, surfactants are most commonly used in soap and detergent. They are also used in many other situations where hydrophobic and hydrophilic ingredients must be combined, but they are often called emulsifiers in these cases. Examples can be found in many foods and personal care products. mine a product of your choice (other than a soap or detergent) that contains a surfactant/emulsifier. Include the name of the surfactant/emulsifier, a brief description of the molecular features that make it a surfactant, and two of the other product ingredients that it is helping to stabilize.