Q. 1. What is chemical reaction?
Q. 2. Which substance is used for white-washing the walls?
Q. 3. What are exothermic reactions? Give one example also?
Q. 4. Name four types of chemical reactions?
Q. 5. What are combination reactions?
Q. 6. Give two example of combination reaction?
Q. 7. What are displacement reactions?
Q. 8. What are double displacemwent reactions?
Q. 9. What are oxidation reactions?
Q. 10. What are reduction reactions?
Q. 11. What is rancidity?
Q. 12. Why do we apply paint on iron articles?
Q. 13. What do you mean by precipitation reaction? Give its one example.
Q. 14. What is redox reactions? Give its two examples?
Q. 15. Write the balanced chemical equation of the following and identify the type of reaction in each case:
i. Potassium bromide(aq) = barium iodide(aq) -> potassium iodide(aq) = bariumbromide(s) ii. Zinc carbonate(s) -> zinc oxide(s) = carbon dioxide(g) iii. Magnesium(s) = hydrochloric acid(aq) -> magnesium chloride(aq) = hydrogen(g)
Q. 16. Wrte an activity to shw the change in the state of matter and change in temperature during a chemical reaction (change).
Q. 17. Write an activity to show the electrolysis of water, as an example of decomposition reaction.
Q. 18. Name different types of chemical reaction? Define them and give their example?
Q. 19. What does the colour of copper sulphate solution change when an iron dipped in it?
Q.20. Write the chemical formula of marble.
Q. 21. Why silver chloride (AgCl) turns grey in