P2 Flashcards
Properties of liquids
Arrangement: Close but not in a regular repeating pattern
Motion: Slide past each other and move to a certain extent
Intermolecular forces: Weaker than solids
Incompressible
Fixed volume
Fixed shape flow
Properties of solids
Arrangement: Closely packed
Motion: Vibrate around a fixed position
Intermolecular forces: Strong between moecules
Incompressible
Fixed volume
Fixed shape no flow
Properties of gas
Arrangement: Randomly and far apart
Motion: Random and fast motion, colliding often
Intermolecular forces: Practically non existent
Compressible
Unfixed volume
Unfixed shape flowss
What is brownian motion
Large Particles suspended in fluids that move randomly
Why does brownian motion occur
they’re colliding with the existing fast moving particles in the fluid
what can be observed in experiments relating to brownian motion
Random movements of suspended particles in a fluid
What does brownian motion prove
The kinetic model of matter as it proves that particles are in constant motion
What does brownian motion prove other than the kinetic model of matter
That large particles can be moved by lighter faster moleculus
What is diffusion
The movement of particles from an area of high concentration to a low concentration
How does molecular mass affect rate of diffusion
The lighter molecular mass the faster rate of diffusion. As they have a higher speed, leading to more collisions, which contribute to a faster rate of diffusion
How does temperature affect rate of diffusion
- higher temp = faster diffusion
- higher internal inergy for particles so move at faster speed
- more collisions
What 2 marks need to be put on a thermometer to calibrate it put degrees on it before use
The lower fixed point (temp. of ice) which should be 0 degrees
The upper fixed point (temp. of steam) which should be 100 degrees.
What properties affect the sensitive of a theometer
A bigger bulb
A liquid with greater expansivity
A thinner capillary tube
What does linearity indicate for therometers
The change in temperature producing the same change in length
What does sensitivy indicate for therometers
The change in length per change in temperature
What does range mean in therometers
difference between the maximum and minimum temperatures that the thermometer can read.
What’s the structure of a thermocouple
2 metal wires made from different metals joined at one making the hot junction where what they measure is placed and then connected to one end of the measuring instrument cold junction
How does a thermocouple work
It relies on the fact the temp. difference between the interection of metal and measuring instrument creates a voltage which is equal to the temperature of that object
Why are thermocouples used
they’re highly responsive and can measure a very high range of temperatures
What’s thermal expansion
- particles receive thermal and energy and vibrate vigorously
- cause spacing between particles to increase, expanding the material
What is thermal expansion caused by
Heat energy through heat that causes particles to vibrate more vigorously
Examples of thermal expansion
Railroad tracks, therometers
Order of magnitude of expansion in states of matter
Gas>Liquid>Solid
Why is gas most sensitive to thermal expansion
- most freedom of motion
- intermolecular forces extremely weak
What changes during changes of state
Arrangement, motion, and closeness
What’s internal energy
The energy of particle motion and chemical bonds
Ranking of internal energy between states
Gas>Liquid>Solid
Do temperatures of substance change during changes of state
No despite energy being transferred they’re used to break bonds which dissipates the temperature.
What do the flat parts of a changing state graph mean
melting, freezing, boiling, condesning, and others
What is evaporation
the surface level change of state from liquid to gas
What kind of particles are eligible for evaporation
fasting moving ones near the surface of a liquid
What does evaporation lead to
the cooling of a liquid as it takes the fastest moving meaning hottest particles away.
Differences between boiling and evaporation
boiling only occurs after a specific temperature is reached, evaporation occurs no matter the temperature
boiling is occuring throughout the liquid, evaporation only happens at the surface
Factors that affect rate of evaporation
Airflow increase evaporation increase
Suface area increase rate of evaporation increase
Temperature increase rate of evaporation increases
What is pressure exactly
Force per unit area caused by molecules hitting the sides of the containor
Is pressure equal throughout a containor
yes as there’s a equal amount of molecules hitting all sides of the containor
What do particles do when they rebound against sides of containors
they exert a force which keeps the shape against atmospheric pressure
What factors affect pressure
temperature within containor as particles with higher speed will have more frequencies of colliosions against a containor
size of containor or volume lesser volume leads to a higher pressures as there’s less distance needed to be travelled to collide against the sides of the containor
What relationship does pressure and volume have
a inverse relationship pressure increases as volume decreases
What is conduction
the transfer of thermal energy by particles bumping against each other
Why are metals the best at conduction compared to gases or liquids
as their arrangement is closely packed and they have delocalised electrons that help pass along the energy
What are examples of good conductors
metals (copper, aluminium, e.t.c)
What are examples of insulators
non-metals (wood and plastic)
What is convection
the main method of energy transfer by fluids, as it requires flow of particles
What is the convection current
- particles heated, move faster, take up more space, decreasing density, float up
- cools, thus sinking down
- pushed by particle behind to recieve heat again
What’s raidation
the transfer of heat by waves most commonly infrare waves
Why can we feel the heat from the sun
radiation and radiation only bc. its only the method of heat transfer that doesn’t require a medium
Properties of surfaces on radiation
Black surfaces; Absorb and emit radiation the best
They will gain and lose heat the fastest
White surfaces: reflect radation the most
It will not be easy for it to gain heat
Matte or dull surfaces: Increase absorption and decrease reflection
Easy to gain heat
Shiny surfaces: Increase reflection and decrease absorption.
Hard to gain heat
