Across
- 1. the heat change during the course of a reaction (also known as heat of reaction): can be either exothermic (a negative value) or endothermic (a positive value)
- 4. change a process or chemical reaction which takes in heat from the surroundings; ΔH has a positive value
- 5. a change in the physical state of a substance or the physical nature of a situation that does not involve a change in the chemical substance(s) present
- 7. a diagram that shows the energy levels of the reactants and products in a chemical reaction and shows whether the reaction is exothermic or endothermic
Down
- 2. the energy required to start a chemical reaction – for a reaction to take place the colliding particles must possess at least this amount of energy
- 3. the energy required to break a particular type of covalent bond
- 4. change a process or chemical reaction in which heat energy is produced and released to the surroundings; ΔH has a negative value
- 6. the thermal (heat) content of a system
- 8. a change in which a new substance is formed