Exercises to the text "Physical Changes"

1. Answer the questions to the text:

  1. Does the molecular structure change when a physical change takes place?
  2. Does liquid oxygen have the same molecular structure as oxygen gas?
  3. Does salt form molecular bond with water being dissolved in it?
  4. When does a mixture occur?
  5. Is there  any change in the molecular structure of the substances in a mixture?
  6. What mixture is lemonade?
  7. What mixture is water?
  8. What does wet concrete consist of?

 

2. Insert a necessary word or word combination:

Liquid, solid, chromium, dissolved, blended, original, wet concrete, cured concrete.

  1.   Molten steel hardens into a ….
  2. … oxygen has the same molecular structure as oxygen gas; each molecule is for … .
  3. Molten steel is made of iron, carbon and small additions of metals such as...
  4. Salt can be … in water. 
  5. A mixture occurs when two or more substances are … .
  6. Each substance in the mixture keeps its … structure and properties.
  7. … is a mixture of water, Portland cement and aggregates (cleaned sand and/or gravels).
  8. …  is a compound.

 

3. Ask as many questions as possible to the following sentences:

  1. A physical change can take place in substances without changing their underlying molecular structures.  
  2. Molten steel changes its physical state while hardening.
  3. Salt can be dissolved in water.