Solid, liquids, gases Flashcards
what is density
Density is a measure of the amount of mass packed into a particular volume
what is density measured in
kg/m (cubed)
g/cm (cubed)
what does the density of an object depend on
what it is made of
what does density determine
whether it floats or sinks
how can you find the density of an object
through its mass and volume
method for finding density for a regular object
use a balance to find its mass
then measure its length, width and height with a ruler to find its volume
then plug the objects mass and volume into density formula
method for finding density for a iregular object
use a balance to measure its mass
then to find its volume by submerging it in a eureka can filled with water.
record the volume of the water in the measuring cylinder (the water which has been displaced)
plug the objects mass and volume into the formula for density
what is pressure
pressure is a measure of the force being applied to the surface of something
what is the relation of force and area and pressure
if there is a same force being applied over a larger area instead of a small area then there will be less pressure
how does pressure act in liquid and gases
at rest, the pressure acts equally in all directions
but pressure increases with depth in liquids and gases
what is pressure difference
the difference in pressure between 2 points in a liquid or gas
what does pressure difference depend on
height difference, density and gravity (gravitational field strength)
what is thermal energy store in particles
The total kinetic and potential energy of the particles in an object (usually the vibrations)
what will heating a system change
it will change the energy stored in a system by increasing the kinetic energy of its particles
what does the increase of thermal energy cause
Cause the temperature of the system to increase
Produce a change of state (solid to liquid or liquid to gas)
how does temperature and kinetic energy relate
The higher the temperature, the higher the average kinetic energy of the molecules and vice versa
what is evaporation
when particles escaqpe from a liquid and become gas particles
what do gas particles near the surface have to do (or be doing)in order to evaporate
travelling in the right direction
travelling fast enough to overcome the attractive forces of other particles
method for a temperature time graph
fill a beaker with crushed ice and place a thermometer in it (record the temp)
using a bunsen burner, gradually heaty the beaker
every 20 seconds record the temperature and current state of the ice
plot a graph
how should a temperature time graph look like (both ways)
what is the scale for the coldest things can be
absolute zero or 0 kelvins
conversion of kelvin and celcius
0 celcius is 273 kelvin
how to convert from celcius to kelvin
add 273 (c->k)
subtract 273 (k->c)
relation of temperature and energy
the temperature of a gas (in kelvin) is proportional to the average energy in the kinetic energy stores of its particles
what is the particle theory
gases consist of very small particles which are contantly moving in completely random directions
the collliding gas particles create pressure
what happens when a solid is heated and melts to a liquid
Thermal energy transfer takes place and supplies the particles in the solid with energy in their kinetic store causing them to vibrate
This partly overcomes the rigid bonds between the particles meaning they can now flow over each other
what happens when a liquid boils to form a gas bubbles are produced within the liquid
Thermal energy transfer takes place and supplies the particles on the surface of the liquid with energy in their kinetic store
when enough of the particles have enough energy to overcome their attraction to each other, big bubbles of gas form in the liquid
explain condensing and freezing
when a substance is condensing or freezing, bonds are forming between particles which releases energy. the temperature doesnt go down until all of the substance has changed state
describe the arrangement and motion of particles in all 3 states of matter
gas vibrate and move freely at high speeds
liquid vibrate, move about, and slide past each other
solid vibrate but generally do not move from place to place
what is the specific heat capacity
the energy required to change the temperature of an object by one degree Celsius per kilogram of mass
what are the units for specific heat capacity
J/kg /°C
what is the aim of the practicle Investigating Specific Heat Capacity
This experiment aims to determine the specific heat capacity of a solid and of water by measuring the energy required to increase the temperature of a known amount by one degree
method for investigating specific heat capacity
Place the beaker on the digital balance and press ‘zero’
Add approximately 250 ml of water and record the mass of the water using the digital balance
Place the immersion heater and thermometer in the water
Connect up the circuit as shown in the diagram, with the ammeter in series with the power supply and immersion heater, and the voltmeter in parallel with the immersion heater
Record the initial temperature of the water at time 0 s
Turn on the power supply, set it at approximately 10 V, and start the stopwatch
Record the voltage from the voltmeter and the current from the ammeter
Continue to record the temperature, voltage and current every 60 seconds for 10 minutes
Repeat steps 2-8, replacing the beaker of water for the solid block of aluminium and starting with recording its mass using the digital balance
what are the ways that gas molecules will change motion
if they collide:
with the walls of its container
with other molecules
what happens when gas molecules colllide with something
they exert a force on it and their momentum and direction change
what happens when gas molecules collide in a sealed container
the exert an ouward pressure
the pressure depends on how fast the particles are going and how often they hit the walls
what happens if you increase the temperature in relation to pressure
if you heat a gas the particles move faster and gain more kinetic energy
this increase in energy means they hit the walls harder and more frequently creating more pressure
showing if you double the temperature (in Kelvin) you double the pressure
what happens if you increase the volume in relation to pressure
if you put the same fixed amount of gas in a bigger container the pressure will decrease because there are fewer collisions between the particles and the walls
definition of absolute zero
The temperature at which the molecules in a substance have zero kinetic energy
why do we have the name absolute zero
At absolute zero, or −273 °C, particles will have no net movement. It is therefore not possible to have a lower temperature
If the temperature of a gas remains constant what will happen with the pressure due to compression and expansion
compressed – decreases the volume which increases the pressure
expanded – increases the volume which decreases the pressure
pressure and volume at a constant temperature
pressure x volume =constant
equation for pressure and volume at a constant temperature
pressure and temperature at constant colume
pressure/temperature(K) = constant
equation for pressure and temperature at constant volume
