Particle model of matter Flashcards
(9 cards)
How can doing work on a gas lead to an increase in temperature
For a fixed mass held at a constant temperature: pV= constant pressure x volume= constant
If you transfer energy by applying a force, work is done, increasing its internal energy and its temperature.
Using a bike pump applies pressure exerting a force and work has to be done against this force to push the pump down.
This transfers energy to the kinetic energy stores of the gas particles and increasing the temperature.
How does temperature increase when a gases temperature increases
Gas particles move at high speeds and bang into anything in their way and when they do this, they exert a force.
Temperature increase, increases the particles’ speed so faster particles and more frequent collisions means an increase in pressure.
Pressure and volume are inversely proportional so at a constant temperature, volume increases so pressure decreases (and the other way round), the particles are more spread out and hit the container walls less often.
How is temperature related to how fast a gases molecules move
If the temperature of a gas increases, energy is transferred into the kinetic energy stores.
A gases temperature relates to the average energy in the kinetic stores so the higher the temperature, the higher the average energy.
As the temperature in a gas increases, the average speed of its particles increases.
What is the difference between latent heat of fusion and latent heat of vaporisation and what’s the specific latent heat equation
Energy (J) = Mass (Kg) x Specific Latent Heat (J/Kg)
The specific latent heat of a substance is the amount of energy needed to change 1kg of it from one state to another without a temperature change.
Specific Latent Heat of Fusion is SLH for changing between solid and liquid.
Specific Latent Heat of Vaporisation is SLH for changing between liquid and gas.
How is the internal energy related to kinetic and potential energy stores
Particles in a system have energy in their kinetic energy stores and in their potential energy stores due to their movement and positions
The internal energy of a system is the total energy that its particles have in other kinetic and potential energy stores.
Heating they system transfers energy to its particles, increasing the internal energy as they move faster, leading to a change in state or temperature.
What are the processes of freezing, condensing, boiling and melting
During condensing or freezing, bonds form which releases energy. The internal energy decreases but the temperature doesn’t until the change of state is completely finished.
During melting or boiling, energy is put in, so the internal energy increases and the energy is used for breaking bonds instead of raising the temperature
Solid-Liquid = Melting
Liquid-Solid = Freezing
Liquid-Gas = Boiling
Gas-Liquid = Condensing
Solid-Gas = Sublimation
Gas-Solid = Deposition
What are the steps to find the density of a solid object
Use a balance to measure the object’s mass.
For obscure-shaped solid, submerge the object in a full eureka can and the water displaced by the object will be transferred to a measuring cylinder beside it.
Record the volume from the measuring cylinder.
Divide the mass by the volume of the object to find the density.
For simple shapes, use volume= width x length x height
What are the differences between solids, liquids and gases
Solids: strong forces, close, fixed and regular arrangement, less energy so vibrate about a fixed position and have a high density.
Liquids: weak forces, move past each other, close and irregular arrangement, more energy than solids, random direction, low speeds and less density
Gas: almost no forces, more energy than both states, move freely, random direction, high speeds and low density.
What is density and what is the equation for it
Density (Kg/m3) = Mass (kg) / Volume (m3)
If an object is dense, its particles are packed closely together.
If an object is less dense, the particles are more spread out.
Solids are denser than liquids.
Liquids are denser that gases.
