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70 terms

chem 13

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unit cell
the smallest group of particles within a crystal that retains the shape of the crystal
crystal
a solid in which the particles are arranged in an orderly repeating pattern
amorphous solid
a solid that lacks an ordered internal structure
allotropes
2 or more diff. molecular forms of an element in the same physical state
evaporation
vaporizing at the surface of a liquid that is not boiling
vaporization
the conversion of a liquid to a gas below the boiling point
boiling point
the temp at which vapor pressure of a liquid is equal to the external
normal boiling point
the temp at which vapor pressure of a liquid is equal to 1 atmosphere
melting point
the temp at which a solid changes to a liquid
sublimationt
he change of a solid directly to a vapor
kinetic theory
all matter consist of tiny particles that are in constant motion
kinetic energy
the energy object has due to its motion
barometer
a device used to measure atmospheric pressure
atmospheric pressure
the pressure resulting from the collision of atoms and molecules with objects
vapor pressure
a measure of the force exerted by a gas above a liquid
according to the kinetic theory collisions between molecules in a gas
are perfectly elastic
which of the following statements is part of the kinetic theory
all the above
the average speed of oxygen molecules in air is about
1700 kn/h
which of the following statements is NOT true according to the kinetic theory
only particles of matter in the gaseous state are in constant motion
particles in a gas are best described as
small hard spheres with significant volumes
which of the following statements is NOT true about the movement of particles in a gas
particles usually travel uninterrupted indefinitely
barometer
instrument is normally used to measure atmospheric pressure
pascal(Pa)
is SI unit of pressure
what is one standard atmosphere of pressure in kilopascals
1 atom/101.3kpa
standard conditions when working with gases are defined as 0*C/101.3kpa
0*C/101.3kpa
how does the atmospheric pressure at altitudes below sea level compare with the atmospheric pressure at sea level
below sea level its higher
what causes gas pressure in a container such as a helium balloon
simutaneous collisions of fast moving particles in container
the pressure of a gas in a container is 152mm Hg this is equivalent to
0.2atm
the temp at wich the motion of particles theoretically ceases is
O K
what happens to the average kinetic energy of the particles in a sample of matter as the temp of the sample is increased
average kinetic energy increases
kelvin
is temp directly proportional to average kinetic energy
what happens to the range of energies of the particles in matter when the temp is increased
the range of energies becomes broader
the average kinetic energy of the particles of a substance__
is directly poportional to the temp of the substance
when a gas is heated__
of the absorbed energy's converted to potential energy and same converted to kinetic energy
Consider an iron cube and an aluminum cube. If the two cubes were at the same temperature, how would the average kinetic energy of the particles in iron compare with the average kinetic energy of the particles in aluminum?
There would be no difference in the average kinetic energies.
The average kinetic energy of water molecules is greatest in
steam at 100C*
what is the key difference between a liquid and a gas
intermolecular attractions
which states of matter can flow
liquids only
What happens to the temperature of a liquid as it evaporates?
decrease
which are the first particles to evaporate from a liquid
particles with the highest kinetic energy
what happens at the rate of evaporation of a liquid as the liquid is cooled
it decreases
why does a liquid's rate of evaporation increase when the liquid is heated
more molecules have enough energy to overcome attract forces holding them in the liquid
Which of the following will evaporate the fastest
water at 40 degrees C
In a dynamic equilibrium between the liquid state and the gas state, what is true about the rate of evaporation?
it is equal to the rate of condensation
If a liquid is sealed in a container and kept at constant temperature, how does its vapor pressure change
it increases at first, then remains constant
An increase in the temperature of a liquid
causes the vapor pressure of a liquid to increase
If energy is added to a boiling liquid what happens to the temperature of the liquid
It does not change
When the vapor pressure of a liquid is equal to the atmospheric pressure, the liquid
begins to boil
what is the pressure when a liquid is boiling at its normal boiling point
101.3kpa
water could be made to boil at 105 degrees Celsius instead of 100 degrees Celsius by
increasing the External pressure
When the external pressure is 505 kPa what is the vapor pressure of water at its boiling point?
505 kPa
The normal boiling point of chloroform, which has a higher vapor pressure than water at 100*C is
Lower than the normal boiling point of water
which of the following best describes the motion of the particles in a piece of steel
all are moving
Compared to melting points of ionic compounds, the melting points of molecular solids tend to be
Lower
most solids
are dense and difficult to compress
Crystals are classified into how many different crystals systems
7
crystals are characterized by particular patterns that repeat in how many dimensions
3 only
unit cell
the smallest group of particles in a crystal that retains the shape of the crystal is called the
how do crystal systems differ
in the angles between faces and the number of edges of equal length
evaporation
The escape of molecules from the surface of hte liquid is known as
which of the following elements has the ability to undergo sublimation
iodine
sublimation
The direct change of a substance from a solid to a gas is called
which of the following is an ex of a phase
water vapor
How are conditions of pressure and temp, at which two phases coexist in equilibrium, shown on a phase diagram
by a line separating the phases
how many faces are in a hexagonal crystal system
8 or 6?
into how many systems are crystals classified
7
how many phases of water are in equilibrium at the triple point
3
gas pressure
results frm the force exerted by a gas per unit sufface area of an object
vacuum
any empty sace w/ no part and no pressure
standrd atmosphere
results from the collisions of atms and loecules in air w/ objects