Interactive - unit 4. lesson 5. observing chemical change

See chemical changes in action! Interactive worksheet on observing chemical reactions.

Evidence of chemical reactionsWatch the video. Then, develop the activities. I. Choose your options1. All things are made of... matter chemicals atoms all of the above 2. Which of the following is a chemical? light gravity air magnetism 3. Which is not a chemical? cotton plastic a wave a protein 4. What would be a simple definition of a chemical reaction? a change in color a change in matter a change in texture a transfer of energy 5. What is an evidence that water is decomposing? gas bubbles an amount of oxygen an amount of hydrogen sparks of electricity 6. What is the most common evidence that iron is reacting with oxygen in the air? a spark of electricity the change in color the transfer of energy an increase in temperature 7. What is most likely happening when you see something burning? atoms recombining electrons recombining molecules recombining all of the above 8. What is the most common evidence that hydrogen is reacting with oxygen to form water? a change in color gas bubbles a transfer of energy the formation of a precipitate II. Match the evidences of chemical reactions with the explanation Release of a gas This is not always an evidence, but very often, gas bubbles can be seen when two substances are put together and change into other substances Change in temperature Very often the temperature of a substance increases when it's turning into another substance Change in color This is not always an evidence of a chemical reaction, but for example, when something is burned it changes into something darker Formation of a precipitate Usually, when two liquid substances or chemicals are dissolved in water, a solid forms, showing an evidence that some matter has changed Transfer of energy If you see light, hear a strong sound, or feel some heat, this is an evidence that some energy is being transfered