Question

hemistry Lesson 1: Chemical reaction and equations 1. Respiration is a _________change 2. When lead nitrate solution is mixed with potassium iodide solution yellow solid formed is ___________ 3. When zinc reacts with hydrochloric acid the gas evolved is _________ 4. The reactions which involve absorption of heat are called ____________reactions. 5. The magnetic oxide of iron is the formula __________ 6. Respiration involves the oxidation of ___________in the body. 7. Dissolution of copper sulphate crystal involves ___________of heat. 8. Reactions which take place in the presence of light are called ____________reactions. 9. Magnesium burns in air to form magnesium oxide this type of reaction is called __________________reaction. 10. That nitrate on heating leaves behind yellow lead oxide this type of reaction is called___________ 11. When water is decomposed electrolytically hydrogen and Oxygen gas obtained in the ratio of ____________ 12. When silver bromide is kept in sunlight for long time the residue left behind is that of___________ 13. When iron nails are kept in copper sulphate solution the blue colour changes to ____________colour. 14. When silver nitrate and sodium chloride reacts name the colour of the precipitate formed in the product 15. Reaction between acid and base is called ___________reaction 16. Write the balanced equation for the following reactions:. Nitrogen combines with hydrogen to form ammonia 17. Why hydrogen peroxide and silver bromide are kept in dark coloured bottle 18. Give an example of a reaction which is double displacement reaction as well as precipitation reaction held simultaneously 19. Write two observation when lead nitrate is heated in a test tube 20. Write the thermal decomposition of lead nitrate chemical reaction and balance it 21. Name the gas which evolves during thermal decomposition of ferrous sulphate 22. Write the chemical formula for hydrated copper sulphate and hydrated ferrous sulphate. 23. Why magnesium ribbon should be cleaned before burning 24. Name the instrument which is used to hold the magnesium ribbon while burning. 25. Give any two examples for physical change and chemical change. Pls help me fast as you can Thank you friends

Answer 1

Answer:

1.Respiration is a physical change

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Explanation: