1. Which of the following are chemical change?

a) Digestion of food b) Liquefaction of air c) Ripening of fruit d) freezing of water e) electrolysis of water.

a) Only a to d. b) only a, b & e. c) a, c, d. d) c, d, e.

2. which among the following is not a physical change?

a) Melting of ice b) vaporization of liquids to gas c) Liquefaction of gases to liquid. D) Decay of matter

3. which among the following is not a chemical change?

a) Melting of ice b) Carbon cycle c) dehydration of substance d) Fermentation of substance

4. Physical changes are usually … in nature.

a) Permanent b) temporary c) irreversible d) endothermic

5. What is the balanced chemical equation for the reaction between methane and oxygen?

a) CH4 + O2 → CO2 + H2O b) 2CH4 + 3O2 → 2CO2 + 4H2O

 c) CH4 + 2O2 → CO2 + 2H2O d) 2CH4 + O2 → CO2 + 2H2O

6. Which of the following is an example of a combustion reaction?

a) 2H2 + O2 → 2H2O b) Fe + CuSO4 → FeSO4 + Cu

c) CH4 + 2O2 → CO2 + 2H2O d) 2NaCl + Pb(NO3)2 → 2NaNO3 + PbCl2

7. What is the product of the reaction between hydrochloric acid and sodium hydroxide?

a) NaCl + H2O b) NaOH + HCl c) NaCl + HCl d) Na2SO4 + H2O

Answer: a) NaCl + H2O

8. Which of the following is an example of a decomposition reaction?

a) Mg + 2HCl → MgCl2 + H2 b) 2H2 + O2 → 2H2O

 c) 2Na + Cl2 → 2NaCl d) 2HgO → 2Hg + O2

9. What is the balanced chemical equation for the reaction between sulfuric acid and sodium hydroxide?

a) H2SO4 + NaOH → Na2SO4 + 2H2O b) H2SO4 + NaOH → NaSO4 + 2H2O

c) H2SO4 + 2NaOH → Na2SO4 + 2H2O d) 2H2SO4 + NaOH → Na2SO4 + 2H2O

10. What is the term used to describe the number of reactants and products in a chemical reaction?

 a) Stoichiometry b) Synthesis c) Decomposition d) Combustion

11. What is the process in which heat is released during a chemical reaction?

 a) Endothermic b) Exothermic c) Neutral d) Equilibrium

12. What is the chemical equation for the combustion of methane gas (CH4) in the presence of oxygen (O2)?

 a) CH4 + 2O2 → CO2 + H2O b) 2CH4 + O2 → 2CO2 + 2H2O

 c) CH4 + O2 → CO2 + H2O d) 2CH4 + 3O2 → 2CO + 4H2O

13. What type of reaction occurs when two or more substances combine to form a single, more complex substance?

 a) Synthesis b) Decomposition c) Combustion d) Displacement

14. What is the balanced chemical equation for the reaction between magnesium (Mg) and hydrochloric acid (HCl) to form magnesium chloride (MgCl2) and hydrogen gas (H2)?

 a) Mg + HCl → MgCl2 + H2 b) Mg + 2HCl → MgCl2 + H2

 c) 2Mg + HCl → MgCl2 + H2 d) 2Mg + 2HCl → 2MgCl2 + H2

15. What is the process in which a single reactant breaks down into two or more simpler substances?

 a) Synthesis b) Decomposition c) Combustion d) Displacement

16. What type of reaction occurs when a more reactive element replaces a less reactive element in a compound?

 a) Synthesis b) Decomposition c) Combustion d) Displacement

17. What is the balanced chemical equation for the reaction between sulfuric acid (H2SO4) and potassium hydroxide (KOH) to form potassium sulfate (K2SO4) and water (H2O)?

 a) H2SO4 + KOH → K2SO4 + H2O b) H2SO4 + 2KOH → K2SO4 + 2H2O

 c) 2H2SO4 + KOH → K2SO4 + 2H2O d) 2H2SO4 + 2KOH → K2SO4 + 2H2O

18. What is the term used to describe a chemical reaction in which the reactants and products have the same chemical formula?

 a) Neutralization b) Redox c) Hydrolysis d) Polymerization

19. Which of the following is not a type of chemical reaction?

 a) Combination b) Decomposition c) Sublimation d) Displacement

20. Which of the following is an example of a combination reaction?

 a) 2H2 + O2 → 2H2O b) NH4NO3 → N2 + 2H2O

 c) 2NaCl → 2Na + Cl2 d) CaCO3 → CaO + CO2

21. In a combustion reaction, which substance is always one of the reactants?

a) Oxygen b) Carbon dioxide c) Water d) Hydrogen

22. In a displacement reaction, which of the following can be always a product?

a) An element b) A compound c) An acid d) A base

23. Which of the following is a balanced chemical equation?

 a) 2H2O2 → 2H2O + O2 b) Ca(OH)2 + 2HCl → CaCl2 + 2H2O

 c) Fe + 2HCl → FeCl2 + H2 d) Na + Cl2 → NaCl

24. Which of the following is an example of a redox reaction?

 a) 2H2O2 → 2H2O + O2 b) Fe + 2HCl → FeCl2 + H2

 c) 2NaCl + Cl2 → 2NaCl2 d) Mg + 2HCl → MgCl2 + H2

25. What is a chemical reaction?

 a) A physical change in matter b) A change in the state of matter

 c) A change in the chemical properties of matter d) A change in the temperature of matter

26. What is a chemical equation?

 a) A written representation of a chemical reaction b) A list of elements in a compound

 c) A formula for a single substance d) A diagram showing the steps of a chemical reaction

27. Which of the following is a reactant in a chemical reaction?

 a) A product b) An intermediate

 c) A catalyst d) A substance that undergoes a change in a chemical reaction

28. What is the law of conservation of mass?

 a) Mass can be created or destroyed in a chemical reaction

 b) Mass is conserved in a chemical reaction

 c) The total mass of reactants and products is not equal in a chemical reaction

 d) The mass of products is always greater than the mass of reactants

29. What is a balanced chemical equation?

 a) An equation that shows the correct order of reactants and products

 b) An equation that has equal numbers of atoms on both sides of the equation

 c) An equation that shows the products but not the reactants

 d) An equation that has more reactants than products

30. What is a catalyst in a chemical reaction?

 a) A substance that does not slows down a reaction

 b) A substance that speeds up a reaction

 c) A substance that changes the products of a reaction

 d) A substance that does not participate in the reaction

31. What is an exothermic reaction?

 a) A reaction that absorbs energy from the surroundings

 b) A reaction that releases energy to the surroundings

 c) A reaction that does not involve a change in energy

 d) A reaction that only occurs at high temperatures

32. What is an endothermic reaction?

 a) A reaction that absorbs energy from the surroundings

 b) A reaction that releases energy to the surroundings

 c) A reaction that does not involve a change in energy

 d) A reaction that only occurs at high temperatures

33. What is the difference between a synthesis reaction and a decomposition reaction?

 a) A synthesis reaction produces more products than reactants, while a decomposition reaction produces more reactants than products

 b) A synthesis reaction involves the breakdown of a substance, while a decomposition reaction involves the formation of a substance

 c) A synthesis reaction combines two or more substances to form a single product, while a decomposition reaction breaks down a single substance into two or more products

 d) A synthesis reaction and a decomposition reaction are the same thing

34. What is a combustion reaction?

 a) A reaction in which oxygen reacts with another substance to produce water

 b) A reaction in which two substances exchange ions to form two new substances

 c) A reaction in which a substance reacts with oxygen to produce energy in the form of heat and light

 d) A reaction in which a solid forms when two liquids are combines together

35. When copper powder is heated, it gets coated with…Top of Form

a) black copper oxide b) yellow copper oxide c) red copper oxide d) none of these

 

Top of Form

 

Top of Form

ANSWERS: 

1

2

3

4

5

6

7

8

9

10

B

D

A

B

C

C

A

D

C

A

11

12

13

14

15

16

17

18

19

20

B

B

A

B

B

D

B

A

C

A

21

22

23

24

25

26

27

28

29

30

A

A

B

D

C

A

D

B

B

B

31

32

33

34

35

 

 

 

 

 

B

A

C

C

A