energy changes

• What occurs during a chemical reaction regarding energy?

  Energy transfers occur
• What is an exothermic reaction?

  Energy is transferred to the surroundings
• What is an endothermic reaction?

  Energy is transferred from the surroundings
• What can energy transfer during a reaction cause?

  Temperature change
• What principle is energy conservation in chemical reactions based on?

  The same amount of energy exists before and after
• What does "the surroundings" refer to in a chemical reaction?

  Everything that isn’t in the reaction
• If a thermometer records an increase in temperature, what type of reaction is occurring?

  Exothermic reaction
• If a thermometer records a decrease in temperature, what type of reaction is occurring?

  Endothermic reaction
• What do reaction profiles show?

  • Whether a reaction is exothermic or endothermic
  • Activation energy is the minimum energy needed for particle collisions
• What happens to energy in an exothermic reaction?

  Energy transfers to the surroundings
• What happens to the temperature of the surroundings during an exothermic reaction?

  Temperature of the surroundings increases
• What occurs when more energy is released when making bonds than is required to break them?

  The reaction is exothermic
• What is a common everyday use of exothermic reactions?

  Self-heating hand warmers
• What happens to energy in an endothermic reaction?

  Energy transfers from the surroundings
• What happens to the temperature of the surroundings during an endothermic reaction?

  Temperature of the surroundings decreases
• What occurs when less energy is released when making bonds than is required to break them?

  The reaction is endothermic
• What holds atoms together in a chemical reaction?

  Strong chemical bonds
• What happens during the breaking and making of bonds in reactions?

  • Breaking bonds requires energy (endothermic)
  • Making bonds releases energy (exothermic)
• What determines if a reaction is exothermic or endothermic based on bond energy?

  Energy balance between breaking and making bonds
• How does the energy released when making bonds affect the overall reaction type?

  It determines if the reaction is exothermic or endothermic
• What is the relationship between energy required to break bonds and the overall reaction type?

  More energy required means endothermic reaction