11786904
Description
Flashcards by finn squires, updated more than 1 year ago
|
|
Created by finn squires
over 6 years ago
|
|
| Question | Answer |
| Describe, using the particle model of matter, solids? | Strong forces of attraction hold particles together in a fixed, regular arrangement. The particles don't have much energy so they can only vibrate about their fixed positions. The density is generally at its highest at this state as the particles are closest together. |
| Describe, using the particle model of matter, liquids? | Weaker forces of attraction between particles, close together but can move past each other. For any substance in a liquid state the particles will have more energy than in solid state. Move in random directions at low speeds. Liquids are less dense than solids. |
| Describe, using the particle model of matter, gases? | Almost no forces of attraction between particles. In a gas state, particles have the most amount of energy. Free to move, travel in random directions at high speeds. Have low densities. |
| What are the two ways of finding an object's density? | 1. use a balance to find its mass, then divide its mass by volume. 2. volume = L*W*H, but for irregular objects use a eureka can. |
| What is the internal energy of a system? | The internal energy of a system is the total energy that its particles have in their kinetic and potential energy stores. |
| What to mass during a change of state? | During a change in state mass is conserved. The number of particles doesn't change, they are just arranged differently. Melting, freezing, subliming, boiling, evaporation, condensing. |
| What is specific latent heat? | The specific latent heat of a substance is the amount of energy required to change 1kg of it from one state to another without changing its temperature. |
| Explain latent heat in terms of a change of state? | When a substance is melting/boiling you are still putting energy in (internal energy increasing), but the energy is used for breaking intermolecular bonds rather than raising the temperature, hence the flat spots on the graph. When a substance is condensing/freezing bonds are forming between particles, which releases energy (internal energy decreases). Temp doesn't go down until all of substances has changed state, hence the flat spots on the graph. |
| What is specific latent heat of fusion? | Solid and liquid (melting/freezing). |
| What is specific latent heat of vaporisation? | Liquid and gas (evaporation/boiling/condensing). |
| How is average kinetic energy related to temperature in a gas? | The particles in gas are constantly moving in different directions at different speeds. If you increase the temperature of a gas, the higher the average kinetic energy in the particles stores increase, increasing the average speed of the particles (1/2mv^2). |
| What is gas pressure? | Gas particles collide with the walls of a container, when they collide they exert a force on it, this is gas pressure. In a sealed container, the outward gas pressure is the total force exerted by all of the particles in the gas on a unit area of the container walls. Faster particles = more freq. collisions = increase net force = increased gas pressure. |
| What things affect gas pressure? | Heating up @ constant volume = increased speed = increased collisions = increased force = increased pressure. Increasing volume @ constant temp = particles spread out = decrease in collisions = decrease in pressure. P is directly proportional to 1/v @ constant temp also p1*v1 = p2*v2. |
| Under what circumstances can a change in pressure mean a change in volume? | Pressure of a gas exerts a net outwards force on a container. Pressure of gases around container push back. If the container can easily change size (balloon) then any change in these pressures will cause the container to compress/expand due to overall force. |
| How can doing work on a gas increase its temperature? | If you transfer energy by applying a force, then you do work. Doing work on a gas increases its internal energy, which CAN increase its temperature. You can apply pressure mechanically e.g. bike pump - gas exerts a pressure (force) on plunger, work has to be done against this force to push down. This transfers energy to the kinetic stores of the gas particles, increasing temp (warm tyres). |
Want to create your own Flashcards for free with GoConqr? Learn more.