Download Pre-AP Chemistry Kinetic Theory and Heat Quiz

Pre-AP Chemistry Kinetic Theory and Heat Quiz
1. According to the kinetic theory, the primary difference in the phases of matter
(of the same substance) is the __speed_ of the particles. Thus, the two factors
that influence which state of matter exists are __pressure_ and temperature.
2. The higher the energy of the particles, the faster they move, the more often
they __collide__, and the less __dense_ the sample of the substance becomes.
Thus, one could say that the primary difference in one state of matter and
another (for the same substance) is the _density_ of the sample. (hint: not
temperature)
3. When comparing different substances in the gas or vapor phase, we find that at
the same temperature and pressure, the molecules of one gas will not move at
the same speed as another. The two primary factors that influence the speed at
which gas molecules move (given constant pressure) are the _size of the
molecule and the temperature of the molecule. The higher the molar mass of
the gas the _slower__ the particles will move at a given temperature.
4. Given the same substance, the solid will have _less__ energy and _less__
entropy (disorder) than liquids; while gases will have _more__ energy and
__more__ entropy than liquids. The motion of the particles in a solid can be
described as _vibrating_ around a fixed point, while the motion of particles in a
gas is described as constant, _random_ motion.
5. Vapor pressure of a solid or liquid can be described as the pressure that builds
up in a _closed_ _container__, as the solid or liquid vaporizes. The vapor
pressure can only be measured once the system reaches a dynamic
_equilibrium__ - where for each particle that vaporizes into the gas phase a
particle _condenses__ into the liquid phase. The higher the normal boiling
point of the liquid or solid, the _lower_ the vapor pressure at equilibrium.
6. Normal boiling point is measured at __standard__ pressure, which can be
expressed as __101.3kPa (or 1.0 atm or 760 mmHg)__. Boiling point can be
defined as the point at which the liquid particles have enough energy to
overcome _atmospheric_ _pressure_, thus at the normal boiling point the
_vapor_ pressure would be equal to _atmospheric__ pressure.
7. The boiling point is the temperature and pressure at which liquid and
gas/vapor__ phases can coexist. The melting point is the temperature and
pressure at which _solid and liquid_ phases can coexist. The triple point is the
temperature and pressure at which _solid, liquid and gas/vapor phases can
coexist. The critical point is the point at which phases of matter __become ill
defined__. The critical temperature is the temperature above which what
cannot happen? a gas cannot be compressed into a liquid The critical pressure
is the pressure it takes to _compress a gas into a liquid at the critical
temperature__.
8. Why do ionic, polar covalent, and nonpolar covalent molecules have a
predictable pattern of boiling point temperatures? (i.e. ionic higher than polar
covalent, which is higher than nonpolar covalent) because of the intermolecular
forces that hold them together - the stronger the intermolecular force the more
energy it takes to separate the molecules to form a gas How will the atoms
present in a polar covalent molecule affect the boiling point? strongest
intermolecular force is hydrogen bonding, molecules where hydrogen bonding
occurs will have higher boiling points than those were dipole or dispersion
force exists
9. How much energy will it take to raise the temperature of 27.5g of ice at 0C to
91.3C?
Q = 27.5g (334 J/g)
Q = 9185
Q = 27.5g (91.3C - 0C)4.184 J/gC
Q = 10505 J
Q = 10505 J + 9185 J
Q = 19700 J
10. What is the mass of a sample of iron if it takes 1235joules of energy to
raise the temperature from 55.6C to 64.7C?
1235 J = X ( 64.7 C - 55.6C) .448J/gC
1235 J = X (4.077 J/g)
303 g = X
11. Which gas will move more rapidly at 98.3C, oxygen or carbon dioxide?
oxygen, because it has a molar mass of 32g/mole, while carbon dioxide
has a molar mass of 44.01g/mole
12. What is the initial temperature of a 24.6g sample of iron, if when it is
immersed in 350.3g of water at 22.3C, it raises the temperature of the
water to 27.4C?
24.6g (X - 27.4C) .448 J/gC = 350.3g (27.4C - 22.3C) 4.184 J/gC
11.0208J/C (X - 27.4C) = 7469 J
11.0207 J/C X - 302J = 7469 J
11.0207 J/C X = 7469 J + 302 J
11.0207 J/C X = 7771 J
X = 706C