Class 7 Science Chapter 5 Physical And Chemical Changes Quiz 39 (25 MCQs)

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1. When turning on the Bunsen burner, where should the air holes be?
2. Which is a Chemical property?
3. A chemical change occurs
4. Exothermic reactions release energy to the surroundings.
5. Is melting ice a chemical or physical change?
6. True or False:According to the law of conservation of mass, mass can be created or destroyed during a chemical reaction.
7. Would enzymes in our saliva that help break down carbohydrates into simple sugars be considered a physical or chemical change?
8. Malleability
9. A car swerves to avoid a collision with an oncoming vehicle and crashes into a tree. The tree falls over. The car is crunched. Liquids pour out of the car onto the street. Based ONLY on those observations, what happened here?
10. What is burning?
11. The formation of a solid when two liquids combine is called?
12. Saliva breaking down carbohydrates into sugars is .....
13. For the equation:2H$_{2}$ + O$_{2}$ $\rightarrow$ 2H$_{2}$OHow much H$_{2}$O will be produced if we react 4g of H$_{2}$ and 32g of O$_{2}$?
14. Baking a cake
15. A change in which new matter is formed, cannot be reversed
16. Which is not a clue that could indicate a chemical change has occurred?
17. Every chemical change involves a transfer of .....
18. When molecules move in a crazy, no patterned way, what state of matter is it?
19. Some substances can be obtained in pure state from their solution by .....
20. A burning candle exhibits
21. Which of the following is NOT a sign of a chemical reaction?
22. Carbon dioxide turns lime water
23. What type of change is photosynthesis?
24. Salt dissolving in water
25. Melting of Wax