Science Worksheet 11 : Chemical Changes in Materials ( Indicators)

• 
  
  Please update your science worksheet according to the answers provided here. This is important . ( By Mr Oh ) 
  
  
  Answers

Pg 13 

Activity 4 : Chemical Properties of acids and alkalis 

Q3. Procedure : Reaction between a metal oxide and an acid 

      Observations : Copper(II) oxide dissolve in the acid to form a pale blue solution. 

Q4. Procedure : Reaction between an alkali and an acid 

     Observation : The universal indicator which was red in hydrochloric acid turned green when sufficient sodium hydroxide was added. 

Q5. Procedure : Reaction between ammonium compounds and an alkali 

 

      Observation : Moist red litmus turned blue. 

Chemical Properties of Acids 

• salt , hydrogen 
• carbon dioxide , water and salt 
• salt , water 

Pg 14 

Continue : Chemical Properties of Acids 

• salt , water , neutralisation 

Chemical Properties of Alkali  

• salt , water , neutralisation 
• salt , ammonia gas and water  ( Heating is required )

Tests for gases 

• Test for hydrogen - lighted , extinguish , lighted and pop
• Test for carbon dioxide - limewater and white 
• Test for ammonia gas - moist , red and blue