Unit 1 Flashcards
Homogenous solutions
Combinations of substances that appear to be one single substance to the naked eye - clean air, drinking water
Heterogenous solutions
Composed of visibly different substances in various phases (solid, liquid, gas)
Differentiating characteristic (intensive properties)
Properties that are unique to the substance in question, and not determined by the amount of it present - melting point, density, conductivity
Extensive properties
Properties that are dependent the amount of substance present - mass, volume
Physical change
A change that does not alter the chemical composition of a substance - phase change
What is the relationship of pressure to phase change points?
Direct relationship - as pressure lowers, PCP lowers - increasing pressure widens the range where substance is stable in one phase
Triple point
A corresponding temperature and pressure where three different phases coexist
Critical point
The point at which the temperature and pressure have both increased to, and the liquid and gas states are indistinguishable
Supercritical fluid
Temperatures and pressures that exceed the critical point create substances that exist in this phase
Vapor pressure curve
The line between liquid and gas on the Temperature-Pressure graphs
Vapor pressure
When a liquid is in a sealed container, some molecules will eventually evaporate, producing a pressure acting on the walls of the container
Increase temp = increase V.P.
What is the boiling point of any given substance?
When the V.P. = ATM - ATM and V.P. are opposing forces. As soon as the temperature is raised high enough (past the B.P), the vapor pressure exceeds the ATM, and the substance evaporates
Can temperature and energy change at the same time?
No - during a phase change, temperature remains steady as the potential energy of the substance increases or decreases. Then temp increases while energy remains the same in all other cases
Filtration
Mechanically separating the components of a substance by running its parts through a filter
Crystallization
Reducing the temperature of a substance to produce crystal solid forms of a component in order to differentiate it
Distillation
Boiling a substance so its most volatile substance evaporates, then putting the remaining liquid into a condenser where parts can continuously be assayed out
Particulate Model of Matter #1
Any macroscopic sample of a substance is made up of an extremely large amount of microscopic particles
Particulate Model of Matter #2
Particles of matter are constantly moving in different directions through empty space, exerting pressure on the walls of its container.
Ideal Gas Constant
Equation that relates pressure P, temperature T, number of particles n, the universal gas constant R, and volume V, as it relates to PMM #2
PV = nRT
What is the purpose of the Particulate Model of Matter?
To predict and explain the physical properties and behavior of substances.
Average Kinetic energy
The energy of motion, expressed as temperature.
<KE> = 1/2 m (<v>^2)
Note: particles of the same substance at 2 coexisting phases at one temperature have the same average kinetic energy
</v></KE>
True or False: At any given temp, individual particles of the same substance can move at different speeds.
True! See figure 1.10 for explanation. In that same graph, you can also infer that the lowest temperature have the lowest average speed (kinetic energy) of the particles.
True or False: Weight and kinetic energy of a substance doesn’t impact velocity.
False! If you throw a baseball and a golf ball exerting the same amount of energy, which is likely to leave your hand faster?
Particulate Model of Matter #3
Particles interact with each other and the strength of the interactions depends on proximity. Repel at short distances, attract at relatively long distances.
