States of Matter Flashcards
Differences btw states of matter are due to relationships among:
average distance of particles, kinds of interactions btw particles, degree of organization of particles
ideal gas
a model of the way that gas particles (molecules and atoms) behave at the atomic/molecular level
The measurement of pressure
is a measurement of force per unit area
What two laws are derived from the four basic gas laws (Boyle’s law, Charles’s law, Avogadro’s law, and Dalton’s law)?
the combined gas law and the ideal gas law
Gas pressure is the result of:
the force exerted by the collision of particles with the walls of the container
Gas pressure is measured with
a barometer, invented by Evangelista Torricelli
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
mercury, 760, 76.0, 1
atmospheric pressure is due to:
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
the kinetic molecular theory of gases explains the behavior of gases by describing:
the bulk properties of a gas result from the action of the individual molecules comprising the gas
Boyle’s law
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
Charles’s Law
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
Combine gas law
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
Avogadro’s law
the relationship between the volume and number of mol of a gas at constant temperature and pressure; V/n=k
molar volume
the volume occupied by 1 mol of any gas
molar volume of any gas at standard temperature and pressure (STP) is:
22.4 L
Ideal Gas Law
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
Explain why the molar volume of helium (or any other ideal gas) is 22.4 L.
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.
Dalton’s Law of Partial Pressures
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
Describe the ideal gas as a model.
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
Radon and nitrogen dioxide are gases at 25 degrees C. which exhibits more ideal behavior? Explain.
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.
Viscosity of a liquid is …
A measure of its resistance to flow; function of both the attractive forces between molecules and molecular geometry
What type of molecules tend to have high viscosity?
Molecules with complex structures and polar molecules
Viscosity generally decreases…
with increasing temperature due to increased kinetic energy overcoming some of the intermolecular attractive forces
Surface tension of a liquid…
is a measure of the attractive forces exerted among molecules at the surface of the liquid (water)
Surface tension generally decreases..
with an increase in temperature or a decrease in the polarity of molecules that make up the liquid
What is a surfactant?
a substance that can be aded to a liquid to decrease surface tension; have polar and nonplus regions at opposite ends of their molecules
vapor pressure of a liquid is defined as …
the pressure exerted by the vapor at equilibrium
boiling point of a liquid is define as ..
the temperature at which the vapor pressure of the liquid becomes equal to the atmospheric pressure; not constant but depends on the atmospheric pressure
normal atmospheric pressure is?
760 torr, or 1 atm
what is the normal boiling point?
the temperature at which the vapor pressure of the liquid is equal to 1 atm
a decrease in vapor pressure results in an ___ boiling point
increased
what are London dispersion forces
temporary dipoles that result when the electron distribution is unsymmetrical; exist with polar and non polar molecules
What are van der Waals forces?
the collective definition of London dispersion forces and dipole-dipole interactions
dipole-dipole interactions only exist with ____ molecules
polar
What is sublimation?
The process in which some molecules in the solid state convert directly to the gaseous state
