Particles Flashcards
Density equation
density (g/cm3, kg/cm3) = mass (kg, g) / volume (cm3)
Density definition
Measure of how compact substance is
Determined whether an object will sink or float
Finding density of a liquid method
Measure mass of empty measuring cylinder using mass balance
Measure mass of cylinder with liquid in it
Measure volume of liquid using measuring cylinder
Find density using formula
Finding density of an irregular solid object method
Measure mass of object using mass balance
Fill eureka can of liquid with known density e.g. water
Place measuring cylinder underneath spout of eureka can
Place object inside of eureka can
If object floats, use finger to submerge object but don’t put finger under water
Continue until no more water spills out
Measure volume of spilt water using measuring cylinder
Find density by using formula
Solid state particles kinetic theory
Strong forces of attraction holding particles close together
Fixed regular arrangement
Not much energy so particles only vibrate
Liquid state particles kinetic energy
Forces of attraction between particles are weaker
Particles close together but can move past each other
Irregular arrangement
More energy than solid particles
Move in random directions at low speeds
Gas state particles kinetic theory
Almost no forces of attraction between particles
Particles have more kinetic energy than liquid particles
Free to move
Move in random directions at high speeds
Cause of state changes
Extra energy in kinetic energy stores, making particles move faster
Overcome forces of attraction between particles
or
Particles slow down enough that forces of attraction overcome their movement
Specific heat capacity rules
Heating a substance increases energy in thermal energy stores
Some materials needs more energy to increase thermal energy stores
They also stay warm longer and release more energy
Specific heat capacity definition
Energy required to raise the temperature of 1kg if a substance by 1°C
Specific heat capacity formula
Change in thermal energy = mass (kg) x specific heat capacity (J/kg°C) x temperature change (°C)
Specific heat capacity of water practical
Use mass balance to find mass of insulating container without and with water (finds mass of water)
Place immersion heater attached to joulemeter and power supply and thermometer into water
Measure temperature of water and turn on power
Stop when temperature has increased
Record temperature change and energy on joulemeter
Rearrange equation to find specific heat capacity
Specific latent heat definition
Energy required to change the state of 1kg of a substance without changing its temperature (for heating)
Energy released by a change in state (for cooling)
Specific latent heat formula
Thermal energy (J) = mass (kg) x specific latent heat (J/kg)
How gas pressure is created
Gas particles collide with each other or other things
This exerts a force
Outward gas pressure = total force exerted by all particles on area of container walls
Factors affecting gas pressure
Temperature
Volume
Pressure and volume formula
P1 x V1 = P2 x V2
Absolute zero definition
When particles have little energy in their kinetic energy stores as possible
-273°C / 0 kelvin
Kelvin in comparison to Celsius
°C +273
Why changes in pressure can cause changes in volume
Changes in pressure change the balance between inward and outward pressure of an object, so the volume changes accordingly
How to change internal gas pressure
Heating
Cooling
How to change external gas pressure
Changing altitude
Pushing a syringe filled with gas hard
Why doing work on gas increases its temperature
Gas exerts pressure (thus a force) on an object
Pushing object down has to be done against the pressure
This transfer energy to kinetic energy stores of gas, increasing internal energy and temperature
What is needed for something to stretch
2 forces acting on it
Elastically distorted definition
When an object can go back to its original shape and length after force has been removed
Inelastically distorted definition
If an object doesn’t return to its original shape and length after force has been removed
Elastic limit definition
Point where an object stops becoming elastically distorted and becomes inelastically distorted
Where energy goes to an elastically distorted object
All energy goes to elastic potential energy store
Force and extension formula
Force = spring constant (N/m) x extension (m)
extension can also be compression
Spring constant factor
Material of object
Stiffer object = greater spring constant
Work done and elasticity formula
Energy transferred in stretching = 1/2 x spring constant(N/m) x extension^2(m^2)
Pressure and force formula
Pressure (Pa) = force (N) / surface area (m^2)
Fluid pressure definition
Pressure caused by collisions of gas or liquid particles on a given surface
Force exerted is always at right angles to any surface in contact with the fluid
Pressure exerted by fluid factors
Area the force is being exerted on Properties of fluid Surrounding atmospheric pressure Depth Density
Pressure due to column of liquid formula
Pressure = depth (m) x density of liquid (kg/m^3) x gravitational field strength (N/kg)
