P3 - Particle Model Of Matter Flashcards
What is density?
Density is the mass per unit volume
What is the equation that links density, mass and volume?
P = M/V
p = density (kg/m^3)
m = mass (kg)
v = volume (m^3)
RP5: Describe a method to determine the density of a regular solid object
RP5: Describe a method to determine the density of an irregular solid object or liquid
Why do objects float?
If the object is less dense than water it floats
If the object is denser than water it sinks
Explain how doing work on an enclosed gas such as a bicycle pump leads to an increase in temperature of the gas
Gas applies pressure to the plunger of the pump , which exerts a force on the plunger
Work has to be done against this force to push down the plunger
This transfers energy to the kinetic energy stores of the gas particles, increasing the temperature
If the pump is connected to a tyre, you should feel it getting warmer
Explain why it is easy to compress a gas, but not solids or liquids
The atoms in gases are more spread out than liquids and solids
Describe the motion of molecules within a gas
Constant random motion
Random directions (erratic)
Random speeds
Compare solids, liquids and gases
Why is mass conserved when a substance changes state?
What type of change are changes of state? How does this differ from chemical changes?
Physical changes
Different from chemical changes because the material recovers its original properties if the change is reversed
What is internal energy?
Internal energy is the total kinetic energy and potential energy of all the particles (atoms and molecules) that make up a system
How does heating change the energy stored within a system?
Increases the energy of the particles in the system, which increases the overall temperature of the system or produces a change of state
During a change of state, what happens to the temperature?
The temperature remains constant. The supplied energy is not used to increase the kinetic energy, but to break the intermolecular forces
If the temperature of the system increases, the increase in temperature depends on what?
Mass of the substance
Type of material
Energy input to the system
What is specific heat capacity?
The specific heat capacity of a substance is the amount of energy required to raise the temperature of one kilogram of the substance by one degree Celsius.
What is the equation that links change in thermal energy, mass, specific heat capacity and temperature change?
∆E = m c ∆θ
∆E = J
mass = kg
specific heat capacity = J/kg °C
∆θ =°C.
What is specific latent heat?
The specific latent heat of a substance is the amount of energy required to change the state of one kilogram of the substance with no change in temperature.
What is the equation that links energy for a change of state, mass and specific latent heat?
E = mL
energy = J
mass = kg
specific latent heat = J/kg
What is the specific latent heat of fusion?
Change of state from solid to liquid
What is the specific latent heat of vaporisation?
change of state from liquid to vapour/gas
Explain how the motion of the molecules in a gas is related to both its temperature and pressure
Changing the temperature of a gas, held at constant volume, changes the pressure exerted by the gas.
What are the factors of pressure on a gas?
Temperature
Volume
What is gas pressure?
Gas pressure is the total force exerted by all of the particles in the gas per unit area
How can a gas be compressed or expanded?
By pressure changes
What is the impact of pressure on gases?
The pressure produces a net force at right angles to the wall of the gas container (or any surface)
At a constant temperature, what effect does increasing volume have on the pressure of a gas?
Increasing volume decreases pressure as particles collide less frequently with the walls
For a fixed mass of gas held at a constant temperature:
What is the equation that links pressure, volume and constant?
pV = constant
pressure, in pascals, Pa
volume, V, in metres cubed, m3
What is work?
Work is the transfer of energy by a force.
