solids, liquids and gases 5 Flashcards
why does heating a system change the energy stored within the system and raise its temperature or state?
heat energy is needed to increase the temperature of an object. the amount of energy needed depends on the masses of an object, type of material it is made from and the temperature increase.
how do objects change state?
SOLID > melts > LIQUID > evaporates/boils > GAS
GAS > condenses > LIQUID > solidifies/boils > SOLID
whats the arrangement of particles in a solid?
close together
a fixed, regular pattern
- strong forces of attraction hold particles close together
whats the movement of particles in a solid?
vibrate on the spot
whats the arrangement of particles in a liquid?
close together
irregular arrangement
- weak forces of attraction between particles
whats the movement of particles in a liquid?
move around each other
random directions
low speeds
- more energy than solid particles
whats the arrangement of particles in a gas?
far apart
random arrangement
whats the movement of particles in a gas?
move quickly in all directions
high speeds
- no forces of attraction between particles
- most energy
practical
show the constant temperature during a change of state:
equipment: bunsen burner, beaker, stearic acid (solidifies and liquid) in boiling tubes, thermometer, stopwatch
method for melting - place boiling tube with the sa in a beaker of water
-place on top of bunsen burner
-start stopwatch
-record temperature every minute until the stearic acid turns into a liquid
method for solidifying - place boiling tube and as in a beaker
-record initial temperature
-start stopwatch and record temperature until the entire quantity of stearic acid has solidified
when plotting temperature and energy input what goes on what axis?
x-axis - energy input
y-axis - temperature
during a change of state, temperature stays…
constant
what is temperature?
measure of how hot something is
what is heat?
measure of thermal energy in an object
whats the measure of specific heat capacity?
J/kg degrees
whats the equation for change in thermal energy?
change in thermal energy = mass x specific heat capacity x change in temperature
practical
the specific heat capacity of materials including water and some solids:
use a thermally insulated container to reduce energy wasted in the surroundings
- use a mass balance to measure mass of container
- fill the container with water and measure the mass again and the change of mass is the water in the container
- set up the experiment with the: thermometer, water, insulating container, electric immersion heater, joulemeter, power supply, voltmeter, ammeter
- make sure joulemeter reads zero
- measure the temperature
- keep an eye on thermometer and when the temperature has increased switch off power and record temperature increase and energy
- repeat experiment to calculate average
why does a temperature time graph plateaus at 0 degrees?
as ice is melting so energy is still being put in but the energy is used for breaking the IMFs
what’s the specific heat capacity of water?
4200J/Kg degrees
what is the relationship between density, mass and volume?
density = mass / volume
what do you do to find the density of a regular-shaped object?
- use a balance to measure objects’ mass
- measure using a ruler the objects: width, length, height
- to find volume times these measurements together
- then use the equation density = mass / volume
what do you do to find the density of an irregularly shaped object?
- use a balance to measure objects’ mass
- to find volume submerge the object in water in an eureka can filled with water, the water displaced will be transferred into the measuring cylinder
- record the volume of water in the measuring cylinder, this is the volume of the object
- then use the equation density = mass / volume
what the relationship between pressure difference, height, density, gravity?
pressure difference = height x density x gravitational field strength
what are the units of density?
g/cm3
kg/m3
what’s the relationship of pressure, force and area?
pressure = force / area
what is pressure measured in?
pa
pascals
what happens to the pressure if the same force is applied over a larger area?
lower pressure
in what direction does pressure act on gases and liquids?
equally in all directions
what is absolute zero?
0 kelvin
-273 degrees
what do you convert from celsius to kelvins?
add 273
what is the particle theory?
gases consist of very small particles which are constantly moving in completely random directions
the particles constantly collide with and bounce of each other and the container walls
what happens if you increase the temperature of a gas?
gases consist of very small particles which are constantly moving in completely random directions
the particles constantly collide with and bounce of each other and the container walls
the increase of temperature of the gas will give the particles more energy, meaning average speed of particles increase
TEMPERATURE OF GAS (IN KELVINS) IS PROPORTIONAL TO THE AVERAGE ENERGY IN THE KINETIC ENERGY STORES OF ITS PARTICLES
what is the temperature of a gas proportional to?
TEMPERATURE OF GAS (IN KELVINS) IS PROPORTIONAL TO THE AVERAGE ENERGY IN THE KINETIC ENERGY STORES OF ITS PARTICLES
what is the particle theory in terms of colliding gas particles and pressure?
gas particles move about and they randomly bang into each other and whatever gets in the way
when they collide they exert a force and their momentum and direction change
in a sealed container, the gas particles smash against container walls creating an outward pressure
pressure depends on how fast the particles are going and how often they hit the walls
what happens to pressure and the particle theory in terms of colliding gas particles when increasing temperature?
particles have more energy and move faster
particles hit walls harder = more pressure
double temperature of a fixed amount of gas = double the pressure
what happens to the pressure and the particle theory in terms of colliding gas particles when you put the same amount of gas into a bigger container?
pressure will decrease as there will be fewer collisions
what is the equation for a fixed mass of gas at a constant temperature?
pressure
pressure x volume = pressure x volume
p1v1=p2v2
what is the equation for a constant volume in a sealed container?
pressure
pressure/temperature (in K) =pressure/temperature (in K)
p1/t1 = p2/t2
