MODEL EXAM 3 ANSWERS(life science-chemistry) G7

Posts : 42 Join date : 2010-01-28

1^st : Life Science

1- STATE IF THE FOLLOWING SENTENCES ARE TRUE OR FALSE , THEN CORRECT THE WRONG SENTENCES 1 marks

1. Endoskeleton of vertebrates doesn’t differ from an arthropod exoskeleton.( F )

………………………………………………is different…………………………………………

2. Earth worms are so harmful to soil. ( F )

………………………………helpful……………………………………………………………….

2-COMPLETE THE FOLLOWING SENTENCES2 marks

1. the phylum sponges are more closely related to cnidarians phylum

2. Eggs are fertilized internally in salamanders and externally in frogs &

toads.

3-GIVE THE SCIENTIFIC REASONS FOR THE FOLLOWING1 marks

Flight and laying eggs are not defining characteristics for birds.

because there other animals can have these characteristics

4-WHAT WOULD HAPPEN IF1 marks

The eggshell of a bird is like the reptile's eggshell

The eggs may be broken when they roll or the bird sits on them

5-LABEL THE FOLLOWING DRAWINGS 1 marks

What is the name of this organism? And what is its phylum and class?

[size=12] Sea star – invertebrate, echinoderms

6- GIVE THE SCIENTIFIC TERM 1 marks

a kind of mammals that develops inside its mother's
body until its body systems can function independently. (placental mammal)
Internal system of fluid filled tubes in echinoderms.. (water vascular system)

7-COMPARE BETWEEN THE FOLLOWING (two items are needed for each): 1 marks

parasite

Free living organism

1. An organism that depends on other organisms for food

2. Such as: tapeworms

1. An organism that depends on itself to get food

2. Such as: planarians

8- ANSWER THE FOLLOWING QUESTIONS1 marks

1. What is gestation period? What is this characteristic for?

The length of time between fertilization and birth – for mammals

2. What is the function of closed circulatory system?

It moves blood through out the body more quickly to transport food and oxygen.

9- CHOOSE THE CORRECT ANSWER 1 marks

1. Kind of worms that live in or on the living organism:

a) Planarians b) tapeworms c) earthworms d) flukes

2. Octopus have…………….…in their head

a) knot of nerves b)large brain. c)no brain d) spots

2^nd : Chemistry

1- STATE IF THE FOLLOWING SENTENCES ARE TRUE OR FALSE , THEN CORRECT THE WRONG SENTENCES

1 marks

1. an element of a symbol Na consists of two combined atoms ( F )

………………………………………is one atom………………………….……………………

2. H₁¹ and H₁² are isotopes of hydrogen ( T )

………………………………………………………….…………………………..…………………

2- COMPLETE THE FOLLOWING SENTENCES 2 marks

1. "Iron form rust in presence of air" this is a chemical property of iron.

2. The solid state of Carbon dioxide is called dry ice and it turns into gas by heating.

3. GIVE THE SCIENTIFIC REASONS FOR THE FOLLOWING1 marks

The melting of ice is endothermic.
Because ice to melt , it must take in heat from the surrounding

4. WHAT WOULD HAPPEN IF1 marks

An atom lost one electron , from its outermost energy level.
It becomes a positive ion

5- LABEL THE FOLLOWING DRAWINGS1 marks

a) This diagram may represent a water molecule. 2

b) How many atoms are there in this molecule?

3

c) What are number 1 and 2 refer to in this diagram ?

1 is two hydrogen atoms

2 is one oxygen atom

6- GIVE THE SCIENTIFIC TERM1 marks

1. A change in which energy is released. (exothermic)

2. Materials that can be hammered or rolled into flat sheets

and other sheets. (malleable)

[b]7- COMPARE BETWEEN THE FOLLOWING 1 marks

elements	At. No.	Mass no.	electrons	Protons	Neutron
₁ H¹	1	1	1	1	0
₆ C¹²	6	12	6	6	6
₂₀ Ca⁴⁰	20	40	20	20	20

8-ANSWER THE FOLLOWING QUESTIONS1 marks

1. A piece of solid object ,does not sink in water, is put in water with a sinker .If the volume of water and the sinker was 25 ml and the volume of water ,sinker and the solid object is 35 ml and the mass of the solid object is 8 gm . Calculate the density of this solid object.

1. the given values and transformations:

V₁ ( water + sinker ) =25ml=25 cm³

V₂ (water + sinker + solid ) = 35 ml = 35 cm³

m = 8 g D =??

2. The law and calculations:

V (solid) = V₂ – V₁ = 35 – 25 = 10 cm³

& Density = mass/volume

D = m / V

D = 8 / 10

D = 0.8 g / cm³

1. What family of the elements in the periodic table contains the most reactive elements?

Alkali metals (Group 1)

9- CHOOSE THE CORRECT ANSWER 1 marks

1. Iron, sand and table salt form a…………..

a)molecule b)compound c) mixture d) solution

2. Which of the following is not describing bromine?

a) Gas in nature b) diatomic c) liquid in nature d) reactive[/b]

THANX SOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO MUCH Mrs.Abdelrahman flower

SAMA

Thanx alot Mr.ABDULR7MAN flower

We appreciate ur hard work with us santa

HOGO

Posts : 42 Join date : 2010-01-28

DEAR HAGAR AND SAMA,
NOT AT ALL,YOU WELCOME.ANY TIME,IF YOU CAN NOT GET ANY POINT PLEASE DO NOT BE HESITATED IN ASKING ME SO I DO MY BEST TO EXPLAIN IT FOR YOU.THANKS

Posts : 5 Join date : 2010-02-07 Age : 27

thank you mrs.abdulrahman

THANX SOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO
OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO MUCH Mrs.Abdulrahman

SAMA

Posts : 42 Join date : 2010-01-28

dear khaleel,
welcome back , the forum is lightning.I hope you tell me if you can not understand any point and tell mazin to get in the forum too.

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