Physics P3+P4 Flashcards
Describe arrangement of solid particles
Strong forces of attraction hold particles close together in a fixed, regular arrangement.
The particles don’t have much energy, so they can only vibrate about their fixed positions.
Describe arrangement of liquid particles
Weaker forces of attraction between the particles. They are close together, but move past each other and form irregular arrangements.
They have more energy than the particles in a solid - they move in random directions at low speeds.
Describe arrangement of gas particles
Almost no forces of attraction between the particles.
The particles have more energy than in liquids and solids - they’re free to move, and are constantly moving with random directions and speeds.
Explain how a gas in a sealed container exerts a pressure on the walls of the 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.
What is internal energy?
The total energy that its particles have in their kinetic and potential energy stores.
What happens to the particles in a substance when that substance is heated?
The particles have more energy in their kinetic stores to break the bonds holding them together
Name the five changes of state
freezing
melting
boiling/ evaporating
condensing
sublimating
Does mass stay the same when a substance changes state?
Yes, mass stays the same
Define specific latent heat (SLH)
The amount of energy needed to change 1kg of it from one state to another without changing its temperature.
What did people used to believe about atoms?
Tiny spheres that couldn’t be broken up
What did the alpha scattering experiment prove? Give 2
1) Atom mass is concentrated in a tiny nucleus at the centre of the atom. Most is empty space.
2) The nucleus has a positive charge, since it repelled the positive alpha particles.
What happens to an electron if it releases EM radiation?
Gain energy -> move to a higher energy level, further from the nucleus
Who proved existence of neutron?
James Chadwick
What is the overall charge of the atom?
Neutral
What is the overall charge of the nucleus?
Positive
