worksheet

Physical and chemical changes

class 7

1.  A change in which a substance undergoes changes in its physical properties is called ( )

a.  Chemical change 

b.   physical change

c.  No change 

d.  Biological change

2.  When carbon dioxide is passed through lime water , then lime water becomes ( )

a.  milky 

b.  shiney 

c.   silvery 

d.  Golden yellow

3.   Brown colour of the apple  after cutting is ( )

a.  physical change

b.  chemical change

c.   no change 

d.   biological change

4.  Ozone layer protects us from harmful ( )

a.  Ultraviolet radiation 

b.   Infrared Radiation 

c.  Visible Radiation 

d.   Heat radiation

5.  The process of depositing a layer of one metal over another metal surface to protect it from rusting is called ( )

a.  Galvanisation 

b.  Crystallisation

c.  amalgamating

d.   Neutralisation

6.  For protecting iron pipes from corrosion, they are coated with ( )

a.  Zinc 

b.  Copper 

c.  Aluminium 

d.   Silver

7.   Metal that is made by mixing iron with carbon, nickel and manganese is called ( ) 

a.  Stainless steel 

b.   German silver

c.  Nichrome 

d.  Eureka 

8.   The process of obtaining Salt by the evaporation of sea water is called ( )

a.  Crystallisation 

b.   Neutralisation

c.  Galvanisation

d.   Amalgamation

9.   Blue colour of the copper sulphate solution changes to Green colour when an iron nail is dropped into it due to the formation of ( )

a.   Iron sulphate 

b.  copper chloride

c.  Copper iron sulphate 

d.   Iron chloride

10. When Magnesium ribbon is burnt in oxygen, the product obtained is ( )

a.  Magnesium chloride 

b.  Magnesium sulphate 

c.   Magnesium oxide 

d.  Iron chloride

11. Magnesium hydroxide, obtained when Magnesium oxide is dissolved in water, is ( ) 

a.  a Base 

b.  An acid

c.   an indicator 

d.   a dissolving agent

12. When Magnesium ribbon is burnt in candle flame it burns with ( )

a.  brilliant red light 

b.  Brilliant yellow light

c.  Brilliant white light

d.   Brilliant Green light

                                                 Class – VII Science (Acids, Bases and Salts)

 1. Which of the following is a strong acid?

 a. Nitric acid b. Citric acid c. Tartaric acid d. Acetic acid

 2. What is the common name of sodium carbonate?

 a. Caustic soda b. Baking soda c. Phenol d. Blue vitriol

 3. Which one of the following metal does not release hydrogen gas with acids?

 a. Iron b. Copper c. Zinc d. Magnesium

 4. Sodium chloride turns

 a. Blue litmus red b. Red litmus blue c. Methyl orange yellow d. No change in colour

 5. Match the following

 Column A                                                                              Column B

 a. Sulphuric acid                                                  i. Neutral salt

 b. Sodium hydroxide                                          ii. Weak base

 c. Citric acid                                                         iii. Strong acid

 d. Calcium hydroxide                                         iv. Weak acid

 e. Sodium chloride                                             v. Strong .

 Fill in the blanks with suitable words.

 a. The sour things we eat contain ---------------.

 b. Ammonium hydroxide is a ----------------.

 c. Milk contains ----------------.

 d. Litmus is extracted from ------------.

 e. An acid contain more ----------------- ions.

7. What is acid rain? How it happen?

 8. Why curd and sour substance should not be stored in metal containers?

 9. Differentiate between strong and weak acids with example?

 10. Rearrange the jumbled letter to obtain name of a indicator.

 a. METURICR b. MUSLIT      c. EEBTOOTR d. HCINA EROS