Science test 6th November

• What are the three states of matter mentioned in the study material?

  Solids, liquids, and gases
• What happens to solids, liquids, and gases when they are heated or cooled?

  They change state
• What processes change the state of substances?

  Evaporation and boiling
• How does a particle model illustrate changes of state?

  It shows how solids, liquids, and gases change state
• What occurs when an ice cube is heated?

  It melts
• What is melting?

  When a solid turns into a liquid as it absorbs energy
• What is boiling?

  When a liquid turns into a gas as it absorbs energy
• What happens during an endothermic process?

  Heat is absorbed during the change of state
• What is an exothermic process?

  It is when heat energy is released during a change of state
• What is the boiling point of pure water?

  100°C
• What is evaporating?

  When a liquid turns into a gas slowly, below its boiling point
• What happens when a gas is cooled?

  It condenses into a liquid
• What are the three states of matter mentioned in the study material?

  Solids, liquids, and gases
• What is freezing?

  When a liquid turns into a solid as it transfers energy to the surroundings
• What is sublimation?

  When a solid turns directly into a gas without becoming a liquid
• What happens to solids, liquids, and gases when they are heated or cooled?

  They change state
• What is dry ice?

  Solid carbon dioxide
• What processes change the state of substances?

  Evaporation and boiling
• Why must dry ice be kept in insulated containers?

  Because it sublimates at temperatures above -78 °C
• What safety precautions should be taken when using heating apparatus?

  Wear eye protection and tie back long hair
• How can a particle model be used in the context of changes of state?

  It shows how solids, liquids, and gases change state
• What are the key processes involved in heating and cooling substances?

  • Heating up:
  • Melting: solid to liquid
  • Boiling: liquid to gas
  • Cooling down:
  • Condensing: gas to liquid
  • Freezing: liquid to solid
• What occurs when an ice cube is heated?

  It melts
• What are the differences between endothermic and exothermic processes?

  • Endothermic:
  • Absorbs energy from surroundings
  • Examples: melting, boiling, sublimation
  • Exothermic:
  • Releases energy to surroundings
  • Examples: freezing, condensing
• How does the addition of salt affect the freezing point of ice in making ice cream?

  • Salt lowers the freezing point of ice
  • Causes ice to melt, absorbing heat
  • Allows the milk to freeze into ice cream
• What is melting in terms of energy absorption?

  It is when a solid turns into a liquid as it absorbs energy
• What happens to the particles in a liquid when it is heated to boiling point?

  The particles gain energy, become widely spaced, and move faster
• What is boiling in terms of energy absorption?

  It is when a liquid turns into a gas as it absorbs energy
• What is the opposite change of state to condensing?

  Boiling
• What is the process used to melt chocolate?

  Heating
• What is the role of energy in changes of state?

  Energy is absorbed or released during the change of state
• What happens to a substance when it is cooled down?

  It can undergo changes of state like condensing and freezing
• How does the arrangement of particles change during boiling?

  Particles gain energy, become widely spaced, and move faster
• What is the temperature at which a pure substance boils?

  The boiling point
• What is the boiling point of pure water?

  100°C
• What is the significance of the particle model in understanding changes of state?

  It helps visualize how particles behave during state changes
• What is evaporating?

  It is when a liquid turns into a gas slowly at temperatures below its boiling point
• What is the purpose of using a Bunsen burner in experiments?

  To heat substances
• Why is it important to work standing up when using heating apparatus?

  To prevent spills from landing on your legs
• What is condensing?

  It is when a gas is cooled and turns into a liquid