Phases and Gases Flashcards
What is stronger, a ion-dipole interaction or a H bond interaction?
ion-dipole interaction is stronger
an increase in entropy is a __1__ value, while a decrease in entropy is a __2__ value
1) + 2) -
How does an increase in IMF affect density
increase in IMF indicates increased density of a substance
Name the process of phase change: 1) solid to liquid 2) liquid to gas 3) gas to solid 4) solid to gas
1) fusion 2) vaporization 3) deposition 4) sublimation
When a gas becomes a solid, does KE increase or decrease? How about entropy? Is this an endo or exothermic rxn?
KE decreases entropy decreases exothermic rxn (bcz your forming bonds, which expels energy)
What is the triple point and critical point of an phase diagram?
triple point: solid, liquid, and gas of that substance coexist in equillibrium (note this doesn’t necessarily mean in equal amounts) critical point: the point where P & Temp difference between liquid and gas is no longer distinct
How does the phase diagram of water differ from the phase diagram of most other substances?
-the slope between solid and liquid is a negative slope, compared to most substances which have a positive slope -this indicates that increased pressure actually promotes the liquid form over the solid form of water (this is because the solid form is less dense than the liquid form). this is the reason why you can glide over ice with ice skates
What is calorimetry?
calorimetry measures changes in heat transfer in a chemical rxn
Distinguish between a bomb, constant pressure, and low tech calorimeter.
bomb calorimeter: measures energy change at a constant volume (therefore allows for changes in pressure) constant pressure calorimeter maintains constant pressure low tech calorimeter: i.e. coffee cup (which maintains contsant pressure) side note: enthalpy changes are the changes in energy at constant pressures. therefore, you cannot use a bomb calorimeter to measure enthalpy.
what is specific heat?
the amount of heat required to raise the temp of 1gram of a substance by 1 degree celsius
what is q in q=mc∆T?
q is change in heat, or change in enthalpy (when pressure is held constant)
When 2 compounds are reacted together and there is a positive change in temperature (aka temperature increases), does this indicate an exothermic or endothermic rxn
exothermic
What are the plateau lines on a heating curve indicate?
the phase changes of that substance. not that these are the areas where heat is added, but the temperature of the substance itself is not increasing. the substance must undergo the phase change before you can further again increase the temperature
What is the first plateau and the second plateau of a heating curve indicate
first plateau - heat of fusion second plateau - heat of vaporization
Is heat of fusion or heat of vaporization higher in value?
heat of vaporization is always higher in value than heat of fusion for all substances
C = mc = heat capacity What is C?
C is usually used and referred to when using a calorimeter
The harder it is to raise the temperature of a substance, the ____ (lower or higher) the value of specific heat, c, will be
higher
Substance A has a lower specific heat than substance B. Which substance will be easier to raise the temperature of that substance?
Raising the temperature of Substance A will be easier
Is the specific heat value for a substance always the same value?
no. the specific heat value will depend on the phase that the substance is in.
As a density of a substance increases, the volume of that substance will _____(decrease or increase)
decrease density and volume are inversely related
What type of relationship does density have to pressure, temperature, and IMF
Density is directly related to pressure, indirectly related to temperature, and directly related to IMF
What is vapor pressure?
the force exerted by the gas particles that vaporize from a solid or liquid sample
is vapor pressure affected by external pressure?
no. the vapor pressure is regarding the pressure that the gas of a substance exerts on that substance, which does not include the pressure of the external environment that is exerted on the substance.
How is vapor pressure related to temperature and IMF?
vapor pressure is directly related to temperature (as temp increases, vapor pressure increases) vapor pressure is indirectly related to IMF (the more IMF of a substance, aka the more polar the substance is, the less the vapor pressure value will be of that substance)
