State of Matter
Which state of matter has a fixed shape and a fixed volume?
Solid
What type of energy is associated with the movement of particles?
Kinetic energy
What is the change of state from a solid to a liquid called?
Melting
What is diffusion?
The net movement of particles from a region of higher concentration to a region of lower concentration.
Describe the arrangement of particles in a liquid.
The particles are close together but arranged irregularly.
What happens to the average kinetic energy of particles when temperature increases?
It increases.
What is the change of state from a gas to a liquid called?
Condensation
Why does the smell of perfume eventually spread throughout a room?
Perfume particles move randomly and diffuse through the air from a region of higher concentration to lower concentration.
Why can a gas be compressed easily?
Because there are large spaces between its particles.
Describe the movement of particles in a solid.
They vibrate about fixed positions.
What happens to particle movement and arrangement during freezing?
The particles move more slowly and become arranged in fixed, regular positions.
In which state is diffusion generally faster: liquids or gases? Explain briefly.
Gases, because their particles move faster and are farther apart.
Explain why a liquid can flow but a solid cannot.
Liquid particles can move or slide past one another, while solid particles only vibrate about fixed positions.
Explain why a gas exerts pressure on the walls of its container.
Moving gas particles collide with the container walls and exert a force on them.
Why does temperature remain constant while a pure substance is boiling?
The energy supplied is used to overcome forces of attraction between particles, not to increase their kinetic energy.
Explain why increasing temperature increases the rate of diffusion.
Particles gain kinetic energy and move faster, so they spread and mix more quickly.
A substance has a fixed volume, takes the shape of its container and is difficult to compress. Identify its state and explain your answer using the particle model.
It is a liquid. Its particles are close together, so it has a fixed volume and is difficult to compress, but they can move past one another, so it takes the container’s shape.
A sealed gas container is heated, but its volume remains constant. Explain why the gas pressure increases.
The particles gain kinetic energy and move faster. They collide with the walls more frequently and with greater force, increasing the pressure.
Compare evaporation and boiling. Give two differences.
Evaporation occurs only at the surface and can happen below the boiling point. Boiling occurs throughout the liquid and happens at a fixed temperature for a pure substance.
Ammonia gas, Mr = 17, and hydrogen chloride gas, Mr = 36.5, are released at opposite ends of a tube. Where will the white ammonium chloride ring form, and why?
It forms closer to the hydrogen chloride end because lighter ammonia molecules diffuse faster and travel farther.