All Class Assessment Grade 8 Chemistry 21-22

 All Class Assessment  Grade 8 Chemistry 21-22

                           Class Assessment

1.    What is this symbol '⇌' used to represent?

A.   dual side reaction

B.   dual side process

C.   reversible reaction

D.   reversible process

      2. When the system A + B  C + D is at equilibrium,

(a) the forward reaction has stopped.

(b) both the forward and the reverse reactions have stopped.

(c) the reverse reaction has stopped.

(d) neither the forward nor the reverse reaction has stopped.

 

3.    Meaning of the word "anhydrous" is

A.   with water

B.   without water

C.   with copper

D.   without copper

 

4.    A reaction in which liquid freezes and its solid form changes into liquid at same temperature, is called

E.   dual side reaction

F.   dual side process

G.  reversible reaction

H.   reversible process

 

5.    The water melts and freezes at

A.   different temperatures

B.   different pressure

C.   same temperature

D.   same pressure

 

6.    Phenolphthalein change color in.

A.  Acids

B.  Alaklis

C.  Water

 

7.    Dye which change color over a specific pH range is.

A.  Acids base indicator

B.  Reactant

C.  Product

 

8.   Equilibrium can be attained only from one side.
a) true
b) false

9.   Equilibrium of a reaction depends on the concentration of reactants.
a) true
b) false

10. In which of the following conditions do you think the rates of both forward and backward reactions are the same?

a) unstable equilibrium
b) not in an equilibrium
c) the beginning of a reaction
d) equilibrium

11. Dynamic equilibrium mainly concerns about _______________

a) spontaneous reactions
b) nonspontaneous reactions
c) reversible reactions
d) Irreversible reactions

12. Dynamic equilibrium is not like a balancing see-saw.
a) true
b) false

13. The position of equilibrium of a reversible reaction can be altered by changing the reaction conditions.
a) true
b) false

14. The effect of temperature on equilibrium has to do with the ----------- of reaction.
a) pressure
b) heat
c) concentration

15. If the volume of a system increases, or the ---------------- decreases, the production of additional moles of gas will be favored.
a) pressure
b) heat
c) concentration

16. Strong acids split up (dissociate) almost completely in water.
a) true
b) false

17. An acid is a substance that donates protons or accepts a pair of valence electrons to form a bond.
a) true
b) false

18. Base as a ------------------------- acceptor.
a) electron
b) proton
c) both

19. Acid as a -------------------- donor.
a) electron
b) proton
c) both

 

1.     Positively charged ions are called cations.
a) true
b) false

2.     Ions are formed by the addition of electrons to, or the removal of electrons from, neutral atoms or molecules or other ions.
a) true
b) false

3.   Outermost shell is known as the -------------.
a) electron
b) valence shell
c) both

4.    Most of the elements need eight electrons in their outermost shell in order to be stable, and this rule is known as the -----------------.

a) electron
b) proton
c) octet rule

5.     Positively charged ions are called cations.
a) true
b) false

6.     Ions are formed by the addition of electrons to, or the removal of electrons from, neutral atoms or molecules or other ions.
a) true
b) false

7.   When negatively charged atom is attracted towards positively charged atom and vice-versa, it is known as -----------------------------. 
a) electron
b) electrostatic attraction
c) both

8.   --------------is a type of linkage formed from the electrostatic attraction between oppositely charged ions in a chemical compound.

a) Ionic bond
b) proton
c) octet rule

9.     The magnesium atom loses 1 electron when it reacts.

a) true
b) false

10.   Ionic compounds are neutral.

a) true
b) false

11.       An oxygen atom has --------------------- electrons in its outer shell.

a) 4
b) 6
c) 8

12.      Magnesium is in Group ---------------------------- of the Periodic Table.

a)            2
b) 3
c) 4

13. The structure of an ionic compound depends on the relative sizes of the cations.

a) true
b) false

14. Ionic compounds are usually formed when metals react with non-metals.

a)   True

b)   false

15. Ionic compounds are solids and are hard to break.

a) true
b) false

16. Ionic compounds have low melting and boiling points.

a) true
b) false

17. Ionic compounds are generally soluble in polar solvents.

a) true
b) false

18. Ionic compounds conduct electricity in the solid-state.

a) true
b) false

19. Water molecules pull the sodium and chloride ions apart, breaking the ionic bond that held them together.

a) true
b) false

20.   Large molecules in which the atoms are held together by ionic bonds.

a) true
b) false

21.                   Giant ionic structures have -------------------------- melting points.

a) low
b) high
c) medium

22.                  A big structure formed by countless ions called-------------------.

a) giant
b) atom
c) cell