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
