Bridge course 8th science test 3

 Q1) 

A)Complete the statement by choosing the right option

I) the frequency of of Audible Sound  is is  20Hz To 2000Hz 

ii) To avoid  sprouting ,Potatoes are exposed to Radiation .

iii) The chemical symbol of calcium is CA

B)Write the answer to the following questions.

i) identify the constellations Shows in the accompanying figure.

Answer:  Scorpio or are vrishchik

i)Solve the puzzle.

1)An ingredients derived  from Petroleum

2) the main compound of natural gas

					K
					E
					R
					O
					S
					E
M	E	T	H	A	N	E
					E

iii) Write examples of natural disinfectants.

 answer: soap nut( Ritha )And Sop pod(ShikaKai) 

Q2)Write the answer to the following questions.

I) draw a vertical intersection of the Hibiscus flower and  label its part

2)Write the scientific name of the animal shows in the picture using Binomial  nomenclature

genus: Bos        Species:taurus

3) What are the important compounds of toothpaste? What are their functions?

 answer: the important Ingredients of the The toothpaste are calcium carbonate and Calcium hydrogen phosphate. These substances remove the dirt from the teeth. They also helped To polish the teeth. Fluoride is also added to toothpaste. This prevents tooth decay fluoride makes the teeth strong. 

4)Under which different types can the following changes be classified ?

i) dissolving

physical , useful, fast, irreversible, non-periodic changes

ii)  a meteor streaking across the Sky

 chemical harmful, fast, irreversible,Non-periodic changes

5) Which molecules contract and relax, while lifting a heavy object from the ground?

 answer: lifting heavy objects from the ground, when molecules contract  there is  movement At the jointAnd the Bones  the move Ether mirror aur away from each other.

Q3) write the answer to the following questions.

1) complete  the Following table. 

Compound	molecules formula	the name of the constituent elements
Sulphuric acid	H2 s o4	hydrogen, sulphur, oxygen
washing soda( sodium Carbonate)	n a0 h	sodium, oxygen, hydrogen
sugar	c C12 h22 o 11	carbon,Oxygen, hydrogen

2)Write the medicinal uses of basil, Amla , neem

Basil: skin ,Debits, digestion, head  cold

 Amla: immunity, health  heart, digestion

 neem: fever and cold

3) complete the following table

4)What is fermentation ? What changes occur in the substance during  this action? Name the substance produced by fermentation in our daily life?

 Answer

  fomentation: fermentation if the chemical process of  conversion Of a  carbonCompound into its another type  by action of microorganism

 The flour Is  fermentedTo produce bread. in batter of Idli and dosa  etc.

 microbial processes used