9. States of Matter

• What happens to energy in an exothermic reaction?

  Transferred to surroundings
• In an endothermic reaction, energy is absorbed from the surroundings
• Evaporation occurs at a specific temperature.

  False
• At what temperature does boiling take place?

  Specific temperature
• Boiling occurs at any temperature.

  False
• At what temperature does evaporation occur?

  Any temperature
• What are the three types of particles that all matter is made of?

  Molecules, ions, atoms
• The three states of matter that students need to know are solids, liquids, and gases
• In the particle model, each particle is represented by a solid sphere.
• What determines the properties of each state of matter?

  Forces between particles
• In solids, there are strong forces of attraction between particles that hold them in a regular lattice
• Solids maintain a definite shape and volume because their particles do not move from their positions.
• What type of movement do particles in a solid exhibit?

  Vibration
• In liquids, there is some force of attraction between the particles, but they can move past each other
• Liquids maintain a definite shape but can change their volume.

  False
• What happens to the speed of particles in a liquid as temperature increases?

  They move faster
• In gases, there is almost no force of attraction between the particles.
• What do gas particles exert on the walls of a container when they collide with it?

  Pressure
• When a substance changes from one state of matter to another, it is called a physical change.
• Melting occurs when particles gain enough energy to break free from their fixed positions in a solid.
• What is the process called when a liquid is cooled and turns into a solid?

  Freezing
• Arrange the following state changes in order of increasing energy absorbed by the particles:

  1️⃣ Freezing

  2️⃣ Condensing

  3️⃣ Subliming
• Match the type of change with its description:

  Physical change ↔️ Reversible change in state

  Chemical change ↔️ Rearrangement of atoms
• In chemical reactions, bonds between atoms break and atoms change places.
• What process occurs when a liquid turns into a gas at a specific temperature?

  Boiling