Chapter 05 – Discussion

Chemical Reactions

• Explain what must happen in order for a process to be considered a chemical reaction.
• In the following list of processes, categorize each as a chemical reaction or not:
  1. An unwashed knife left in the sink starts forming orange spots.
  2. A cup of ice water left outside slowly turns into water.
  3. Table salt is poured into a glass of water and dissolves.
  4. A piece of bread is put into a toaster and turns dark brown.
  5. A block of limestone is crushed into a powder.
  6. As bread is cooking, the baking soda turns into a gas to raise it and make it fluffy.
• Identify a process in your life that can be classified as a chemical reaction. Describe the reactants and products associated with this process.

Chapter 05 – Discussion

• Explain what must happen in order for a process to be considered a chemical reaction.

For a process to be considered a chemical reaction, the change in the materials involved must be permanent. There may be discoloration, evolution of gas, dehydration (wetting of the product), and/or formation of solids. In other words, it must not only change the physical dimensions (state of matter, length, width, and height) but also the characteristic of the substance.