Particle Nature of Matter Flashcards
In terms of particles. What are solids like.
Strong forces of attraction between particles. Particles are packed together in a fixed pattern. Atoms vibrate but can’t move. Solids have fixed volume, shape and high density.
In terms of particles. What are liquids like
Weaker attractive forces in liquids than in solids, particles are close in an irregular, unfixed pattern
Particles move and slide past each other which is why liquids adopt the shape of the container they’re in. Liquids have a fixed volume but not a fixed shape and have a moderate to high density
In terms of particles. What are gas’s like
Particles are in random movement, move quickly in all directions and collide against each other. No fixed volume, since there is a lot of space between the particles. Gases have a low density
From solid to liquid do the intermolecular forces become weaker or do they just decrease in number without the force changing
The intermolecular forces don’t weaken but become less allowing liquid to move more freely
In terms of particles. What are gases
Particles in gases are far apart and move fast colliding with each other. No fixed volume since there is a lot of space between particles. Gases can be compressed in low volume. Gases have low density
What is melting
Melting is when a solid changes into a liquid
Requires heat energy which transforms into kinetic energy, allowing the particles to move
What is boiling
Boiling is when a liquid changes into a gas
Requires heat which causes bubbles of gas to form below the surface of a liquid, allowing for liquid particles to escape from the surface and within the liquid.
What is freezing
Freezing is when a liquid changes into a solid
This is the reverse of melting and occurs at exactly the same temperature as melting, hence the melting point and freezing point of a pure substance are the same. Water for example freezes and melts at 0ºC
What is evaporation
When a liquid changes into a gas. Evaporation occurs only at the surface of liquids where high energy particles can escape from the liquid’s surface at low temperatures, below the b.p. of the liquid
The larger the surface area and the warmer the liquid/surface, the more quickly a liquid can evaporat
No heat is required and evaporation occurs over a range of temperatures
Condensation
When a gas changes into a liquid, usually on cooling. When a gas is cooled its particles lose energy and when they bump into each other, they lack energy to bounce away again, instead grouping together to form a liquid
What sublimation
When a solid changes directly into a gas
This happens to only a few solids such as iodine or solid carbon dioxide. E.g carbon to carbon dioxide
The reverse reaction also happens and is also called sublimation (sometimes called deposition or desublimation)
What does a reversible arrow mean
Reversible reaction
What does an increase in temperature do to particles
It makes the particles move faster therefore creating more kinetic energy.
Thermal energy —> kinetic energy
How come the pressure of inside a gas container is way more than and opened container
Particles are bouncing way more and colliding way more creating more kinetic energy and pressure
An increase in temperature does what to pressure
An increase in temperature gives particles more energy resulting in an increase in kinetic energy making particles collide against each other more and move faster therefore increasing temperature.
Increase in temperature —> increase in pressure
