Chemistry

• 1. what is the purpose of an indicator in a chemical experiment

      to show different colors in acids and bases
• 2. What is used in ' making the red cabbage indicator ' to grind the cabbage

         Pestle and mortar
• 3. What is the color of the red cabbage indicator when in contact with sodium hydroxide

        purple
• 4. why was the crushed cabbage heated with water in the experiment

      To extract the colors
• 5. What effect would curning red cabbage indicator yellow have on universal indicator

  Turn it red
• 6. What is neutralization

      A. reaction between acids and alkalis
• 7. what is the word equation for neutralisation

      Base + acid = water + salt
• 8. in a neutralization reaction what results from the reaction between acids and alkalis

     Salt and water
• 9. What % of oxygen is in the air

     20-21%
• 10. What is the general word equation for the determination of oxygen using copper metal

             Copper + oxygen = copper oxide
• 11. how is oxygen removed from the air in the experiment to determine its percentage

            by passing over copper metal
• 12. what is the main residual gas after oxygen removes in the experiment

       nitrogen
• 13. what change in appearance does copper undergo during the experiment to

  Brown to Black
• 14. what type of change its decomposition of hydrogen peroxide

      chemical
• 15. what gas is produced by the decomposition of hydrogen peroxide

       oxygen
• 16. what is the purpose of the black solid compound in the decomposition of hydrogen peroxide

                to speed up the reaction
• 17.  what color is oxygen

          colorless
• 18. what is the symbol for oxygen

  O
• 19. which gas is the. major part of air

        nitrogen
• 20. Is decomposition a physical or chemical change

  chemical
• 21. what common name do we give to the oxide of hydrogen

  water
• 22. what do we use to measure the pH of solutions

  universal indicator
• 23. what is the color of oxygen

  colorless
• 24. what is the test for oxygen

  re-lights a glowing splint
• 25. what is the test for co2

  limewater turns cloudy