📚Science: Chemical Reactions📗

• What is an exothermic reaction?


  A chemical reaction that releases energy to the surroundings, increasing temperature.
• What is an endothermic reaction?


  A chemical reaction that takes in energy from the surroundings, decreasing temperature.
• What happens to the mass of products if a reactant is a gas?


  It may appear that the mass of the products has increased.
• What are reactants in a chemical reaction?


  Substances at the beginning of a chemical reaction (before the arrow in a word equation).
• What are products in a chemical reaction?


  Substances at the end of a chemical reaction (after the arrow in a word equation).
• What is the effect of a gas product on the mass of the products?


  It may appear that the mass of the products has decreased.
• What is complete combustion?


  Combustion that occurs with plenty of oxygen available.
• What is incomplete combustion?


  Combustion that occurs with limited oxygen available.
• What is combustion?


  When a fuel burns, it is an example of an exothermic reaction.
• What happens during complete combustion?


  More energy is released.
• What happens during incomplete combustion?


  Less energy is released.
• What is thermal decomposition?


  When a substance breaks down when heated, an example of an endothermic reaction.
• What is the chemical equation for the thermal decomposition of metal carbonate?


  Metal carbonate → metal oxide + carbon dioxide.
• What are the differences between exothermic and endothermic reactions?


  • Exothermic: Releases energy, temperature increases.
  • Endothermic: Absorbs energy, temperature decreases.
• What are the types of combustion?


  • Complete combustion: Plenty of oxygen available.
  • Incomplete combustion: Limited oxygen available.
• What is the significance of thermal decomposition in chemistry?


  • Involves breaking down substances when heated.
  • Example of an endothermic reaction.
• Decomposition reactions involve a single compound breaking down into two or more simpler substances.
• Single displacement reactions occur when one element replaces another element in a compound.
• Combustion reactions involve a substance rapidly reacting with oxygen to produce heat and light.
• Chemical reactions can be represented using equations that show how many molecules or formula units of each substance take part in the reaction.
• The equation shows how many molecules or formula units of each substance are involved in the reaction.