Studied by 98 people
define titration
a technique used to determine the concentration of a solution of known concentration
titration experiment description
a titrant (solution of known concentration) is added to analyte (solution of unknown concentration) until there is a color change (endpoint) which ideally is a close approximation of the equivalence point (when moles of titrant equal the moles of analyte); the volume of titrant (mL) and titrant analyte are divided by volume of anyalyte to determine analyte concentration (mol/L)
The four properties that determine the behavior of gas
the amount of gas (in moles), the volume, the temperature (in Kelvin), and pressure
Write the ideal gas equation
PV=nRT
Physical basis of gas pressure =
gas molecules colliding with the walls of their container
Qualitative relationships between gas pressure and other factors
effect of volume - if you decrease the volume, gas molecules collide more frequently with the walls of their container therefore pressure increases and vice versa
effect of temperature - if you increase the temperature, gas molecules move faster and strike the container walls more frequently; therefore pressure increases and vice versa
effect of number of moles - if you increase the number of moles, there are more collisions with the container; therefore pressure increases and vice versa
Barometer purpose
to measure atmospheric pressure
Cause of atmospheric pressure
the weight of air molecules pressing down on an object
Draw the barometer diagram
standard atmospheric pressure description
at sea level, the column of mercury in a barometer is 760 mm tall; therefore, the standard atmospheric pressure is denoted as 760 mmHg or 1 atmosphere (1 atm)
Converting between different pressure units
1 atm = 760 Torr = 760 mmHg
Define Boyle's Law
the volume of a gas is inversely proportional to the pressure when the temperature and number of molecules remains constant
Write out Boyle's expression
Draw Boyle's Graph
Draw Boyle's Experiment
What is the equation for Boyle's law?
P1V1=P2V2
What is the reasoning for Boyle's Law equation?
Use PV=nRT and isolate the variables that are changing
set initial = final
Define Charles' Law
the volume of a gas is directly proportional to the Kelvin temperature under conditions of constant pressure and constant number of moles of gas
Write out Charles' Expression
Draw Charles' graph
What is the equation for Charles' Law?
V1/T1=V2/T2
What is the reasoning for Charles' Law equation?
Use PV=nRt and isolate the variables that are changing
set initial equal to final
What is the direct relationship concept?
when one property goes up, the other property goes up and vice versa
What is an example of the direct relationship concept?
when temperature of a gas goes down, the volume goes down also
What is the other criterion for a direct relationship?
when the value of one property is zero, the value for the other property is zero as well
Define inverse relationship
when one property goes up, the other goes down and vice versa
What is an example of an inverse relationship?
when the volume of a gas goes down, the pressure goes up
Define absolute zero
the coldest theoretical temperature at which the volume and pressure of a gas becomes zero
The value of absolute zero in Kelvin is
0K
the value of absolute zero in C is
-273.15C
What is the formula to convert Celsius to Kelvin?
K=C+273
what are the 5 keys to solving gas problems?
reason to get the right equation
use algebra to solve for the right variable
make sure the units cancel
make sure the temperature is in kelvin when you plug it into an equation
consider diatomic elements for molar mass
The standard temperature for gases is
0C(273K)
the standard pressure for gases is
1 atm
Avogadro's Law says that
the volume of a gas is directly proportional to the number of moles of the gas under conditions of fixed temperature and pressure
Draw the diagram and description of the difference between ideal and non-ideal gas in terms in container volume
Draw the diagram of the difference between ideal and non-ideal gas in terms in container volume
Write the description of the difference between ideal and non-ideal gas in terms in container volume
in an ideal gas, the molecules do not interact with each other, therefore they bounce off of each other without losing speed, therefore, gas pressure (collisions with container walls) is not affected by collisions between the gas molecules.
Properties that you want if you want your gas to behave ideally
you want large volume and high temperature, and/or low pressure
Define thermochemistry
the branch of chemistry concerned with the heat changes that accompany chemical reactions
System definition
the object or objects being studied
surroundings definition
everything outside the system that can exchange energy and/or matter with the system
potential energy definiton
the energy that matter possesses due to its condition (hot), position (internuclear distance), or composition (hydrocarbons)
potential energy and temperature relationship
a hot substance has more potential energy than a cold substance
Draw the internuclear distance diagram
Draw the potential energy vs internuclear distance diagram
Potential energy and composition relationship
hydrocarbons are molecules made mostly of carbon and hydrogen; therefore, molecules with this composition can undergo combustion reactions, and therefore have the potential to produce lots of energy
Kinetic energy definition
the energy that matter possesses due to its motion
Heat definition
the energy that flows from a warmer object to a colder object; it is a measure of total energy
Calorie definition
the amount of heat required to raise the temperature of one gram of water to 1 degree Celsius
Converting between calories and joules
1 cal = 4.184 J
Specific heat definition
the amount of heat required to raise the temperature of one gram of substance by 1 degree Celsius
what are the units of specific heat?
cal/gC
heat capacity defintion
the quantity of heat required to change the temperature of a system by one degree celsius
electrostatic interaction definition
the attractions and repulsions between molecules
Draw the diagram that explains electrostatic interactions
Describing the state of a system
We must indicate its temperature, pressure, and the kinds and amounts of substances present
State function definition
a property that has a unique value for a specific state of the system
State function example
If you prepare three samples of pure water in different ways (distillation, burning pure H2 in pure O2, or condensing pure water vapor ) and get them all to the same state, their densities will be the same
Enthalpy change definition
this is a special kind of heat; it is under constant pressure
Thermochemical equation definition
a balanced chemical equation that shows the heat involved in the reaction
thermostoichiometry definition
unit analysis tool used for thermochemical equations
Draw the heat curve for water example
Heat of fusion definition
the amount of heat required to turn one gram of substance from solid to liquid
Heat of solidification definition
the amount of heat released when turning one gram of substance from liquid to solid
Heat of vaporization definition
the amount of heat required to turn one gram of substance from liquid to gas
Heat of condensation definition
the amount of heat released when turning one gram of substance from gas to liquid
