States of Matter

Question 1

Differences btw states of matter are due to relationships among:

Answer 1

average distance of particles, kinds of interactions btw particles, degree of organization of particles

Question 2

ideal gas

Answer 2

a model of the way that gas particles (molecules and atoms) behave at the atomic/molecular level

Question 3

The measurement of pressure

Answer 3

is a measurement of force per unit area

Question 4

What two laws are derived from the four basic gas laws (Boyle’s law, Charles’s law, Avogadro’s law, and Dalton’s law)?

Answer 4

the combined gas law and the ideal gas law

Question 5

Gas pressure is the result of:

Answer 5

the force exerted by the collision of particles with the walls of the container

Question 6

Gas pressure is measured with

Answer 6

a barometer, invented by Evangelista Torricelli

Question 7

1 standard atmosphere (1 atm) of pressure is equivalent to a height of ______ that is equal to _____ mm Hg, ___ cm Hg, and __ mm of Hg

Answer 7

mercury, 760, 76.0, 1

Question 8

atmospheric pressure is due to:

Answer 8

the cumulative force of the molecules of air (N2 and O2, for the most part) that are attracted to the earth’s surface by gravity

Question 9

the kinetic molecular theory of gases explains the behavior of gases by describing:

Answer 9

the bulk properties of a gas result from the action of the individual molecules comprising the gas

Question 10

Boyle’s law

Answer 10

the volume of a gas varies inversely with the pressure exerted by the gas if the number of mol and temperature of gas are held constant (think of a balloon); PiVi=PfVf

Question 11

Charles’s Law

Answer 11

states that the volume of a gas varies directly with the absolute temperature (K) if pressure and number of mol of gas are constant. Vi/Ti=Vf/Tf

Question 12

Combine gas law

Answer 12

derived from Boyle’s law and Charles’s law to determine a fixed mol of gas that undergoes change involving volume, pressure, and temperature simultaneously; PiVi/Ti=PfVf/Tf

Question 13

Avogadro’s law

Answer 13

the relationship between the volume and number of mol of a gas at constant temperature and pressure; V/n=k

Question 14

molar volume

Answer 14

the volume occupied by 1 mol of any gas

Question 15

molar volume of any gas at standard temperature and pressure (STP) is:

Answer 15

22.4 L

Question 16

Ideal Gas Law

Answer 16

combines Boyle’s law (relating V and P), Charles’s law (relating V and T), and Avogadro’s law (relating V and mol); PV = nRT

Question 17

Explain why the molar volume of helium (or any other ideal gas) is 22.4 L.

Answer 17

The molar volume is based on 1 mol of ANY ideal gas. for any ideal gas, all quantities substituted in the ideal gas equation are independent of the identity of the ideal gas.

Question 18

Dalton’s Law of Partial Pressures

Answer 18

A mixture of gases exerts a pressure that is the sum of the pressures that each gas would exert if it were present alone under the same conditions; ASSUMING that the behavior of each gas in a mixture of gases is INDEPENDENT of all the other gases

Question 19

Describe the ideal gas as a model.

Answer 19

Describes the behavior of individual atoms and molecules; this behavior translates to the collective properties of measurable quantities of these atoms and molecules; does not account for differences between polar and non polar gases, as well as other interactive forces

Question 20

Radon and nitrogen dioxide are gases at 25 degrees C. which exhibits more ideal behavior? Explain.

Answer 20

Radon (Rn) is a collection of atoms (recall that all atoms are inherently non polar), and nitrogen dioxide (NO2) molecules are polar. Since non polar molecules are only weakly attracted to each other, they exhibit more idea gas behavior.

Question 21

Viscosity of a liquid is …

Answer 21

A measure of its resistance to flow; function of both the attractive forces between molecules and molecular geometry

Question 22

What type of molecules tend to have high viscosity?

Answer 22

Molecules with complex structures and polar molecules

Question 23

Viscosity generally decreases…

Answer 23

with increasing temperature due to increased kinetic energy overcoming some of the intermolecular attractive forces

Question 24

Surface tension of a liquid…

Answer 24

is a measure of the attractive forces exerted among molecules at the surface of the liquid (water)

Question 25

Surface tension generally decreases..

Answer 25

with an increase in temperature or a decrease in the polarity of molecules that make up the liquid

Question 26

What is a surfactant?

Answer 26

a substance that can be aded to a liquid to decrease surface tension; have polar and nonplus regions at opposite ends of their molecules

Question 27

vapor pressure of a liquid is defined as …

Answer 27

the pressure exerted by the vapor at equilibrium

Question 28

boiling point of a liquid is define as ..

Answer 28

the temperature at which the vapor pressure of the liquid becomes equal to the atmospheric pressure; not constant but depends on the atmospheric pressure

Question 29

normal atmospheric pressure is?

Answer 29

760 torr, or 1 atm

Question 30

what is the normal boiling point?

Answer 30

the temperature at which the vapor pressure of the liquid is equal to 1 atm

Question 31

a decrease in vapor pressure results in an ___ boiling point

Answer 31

increased

Question 32

what are London dispersion forces

Answer 32

temporary dipoles that result when the electron distribution is unsymmetrical; exist with polar and non polar molecules

Question 33

What are van der Waals forces?

Answer 33

the collective definition of London dispersion forces and dipole-dipole interactions

Question 34

dipole-dipole interactions only exist with ____ molecules

Answer 34

polar

Question 35

What is sublimation?

Answer 35

The process in which some molecules in the solid state convert directly to the gaseous state