Atoms and Molecules Revision MCQ Questions

1.    A beaker of nitrogen was inverted over a porous pot containing carbon monoxide as shown. The water level did not change. What is the reason for this? A2M Q1.PNG

A    Both gases are diatomic.

B    Nitrogen is an unreactive gas.

C    The gas particles are too large to pass through porous pot.

D    The two gases have the same density.


2.    Hydrogen chloride is very soluble in water, whereas chlorine is only slightly soluble in water. Both gases can be dried using concentrated sulfuric acid. Which diagram represents the correct method of obtaining dry chlorine from damp chlorine containing a small amount of hydrogen chloride?

A2M Q2.PNG




Answer:

1.    D

2.    B

Advertisements

Atomic Structure Revision Structured Question

The following diagram was obtained from an analysis of naturally-occurring isotopes of chlorine.

Atomic structure SQ.PNG

(a)    Define the term ‘isotopes’.

 

 

(b)    Using the diagram, calculate the relative atomic mass of a sample of
naturally occurring chlorine.

 

 

 

(c) What is the difference between Chlorine-37 and Chlorine-35?

 

 

 




Answer:

(a) Isotopes are atoms of the same element with the same number of protons but                 different numbers of neutrons.

(b) (0.75)x 35 + (0.25)x37 = 35.5

(c) Chlorine-37 contains 17 protons and 20 neutrons in its nucleus while Chlorine-35         contains 17 protons and 18 neutrons in the nucleus.

OR Chlorine-37 has 2 more neutrons than chlorine-35
[reject: the different numbers of neutrons]
[reject: chlorine-37 has a mass number of 37 while chlorine-35 has a mass number       of 35]

Atomic Structure Revision MCQ Questions

1.    Two particles having the same numbers of protons and neutrons but different number of electrons might be an atom and

A    an ion of different elements.

B    an ion of same element.

C    an isotope of different elements.

D    an isotope of the same element.


2.    Why are the elements sodium and chlorine in the same Period of the Periodic Table?

A    Sodium is a reactive metal and chlorine is a reactive non-metal.

B    Sodium and chlorine combine together to form a compound of formula
NaCl.

C    The atoms of both elements have only three electron shells containing
electrons.

D    The atoms of both elements have eight electrons in their second
electron shell.


3.    The formulae of the ions of some elements are shown below.

N3-    O2-    F    Li+    Mg2+

Which statement about these ions is CORRECT? They all have

A    the same number of electrons in their outermost shells.

B    the same electronic structure as a noble gas.

C    the same number of neutrons in their nuclei.

D    more electrons than protons.


4.    In which one of the following sets do all 3 particles have the same total number of electrons?

A    CI, Br, I

B    F, Ne, Na+

C    H, H, H+

D    S2-, SO3, SO32-




Answer:

1.    B

2.    C

3.    B

4.    B

 

Seperation Techniques Revision Structured Question

Some inks are dyes dissolved in water. The apparatus below illustrates how water may be seprated from these inks.

ST SQ.PNG

(i)     On the diagram, label the ink and the pure water.

(ii)    On the diagram, draw a thermometer to show where it should be placed so as to collect pure water in the experimental set-up.

(iii)    Name this method of separation.

 

 

(iv)    What is the purpose of the beaker of cold water?

 




Answer:

(i and ii)

ST SQ.PNG

 

 

 

 

 

 

(iii) Simple distillation

(iv) To condense the water vapour.

 

Seperation Techniques Revision MCQ Questions

1.    Which of the following pairs of substances can be separated by heating?

A    Ammonium chloride and iodine

B    Potassium iodide and copper (II) sulfate

C    Copper (II) sulfate and sodium chloride

D    Sodium chloride and ammonium chloride


2.    Two liquids have the same boiling point and are completely soluble in each other. Which method would you use to try to separate them?

A    chromatography

B    fractional distillation

C    filtration

D    using separating funnel


3.    Copper(II) sulfate crystals can be separated from sand using the four processes listed below. The order in which these processes should be used is

             1st                     2nd                            3rd                                 4th
A     filtration          solution              crystallization             evaporation

B      solution         evaporation              filtration                 crystallization

C     filtration           solution                evaporation              crystallization

D     solution            filtration              evaporation               crystallization


4.    At which temperature does a concentrated aqueous solution of sodium chloride begin to boil?

A    96oC

B    99oC

C    100oC

D    104oC


5.      A chromatography experiment was carried out using a drop of a solution of an alloy, German silver. The results is shown below:

ST Q5.PNG

We can conclude that the metals present in German silver are

A    aluminium, copper and nickel.

B    aluminum, nickel and silver.

C    copper, nickel and zinc.

D    copper, silver and zinc.


6.     A sample of solid X melts gradually over a large range of temperatures. However, the liquid that is formed on heating solid X solidifies at one temperature. This sample most likely contains

A    a pure compound.

B    a mixture of compounds miscible in the liquid state.

C    a mixture of two or more compounds that combine to form a new compound when solid X was melted.

D    a mixture of compounds immiscible in the liquid state.


7.    Two liquids, dichloromethane and water, are separated using separating funnel. Dichloromethane is drained off first.

Which statement about dichloromethane is correct?

A    It is miscible with water and is denser than water.

B    It is immiscible with water and is less dense than water.

C    It is miscible with water and is less dense than water.

D    It is immiscible with water and is denser than water.




Answer:

1.    D

2.    A

3.    D

4.    D

5.    C

6.    C

7.    D

Qualitative Analysis Revision Structured Question

QE Structured Q.PNG

(ai)    Write the chemical formula for A, B, C and M.

A:

B:

C:

M:

 

(ii)    Give the ionic equation, including the state symbols, for the formation of the dirty green precipitate.

 

(b)    A colourless solution is suspected to contain either aluminium or lead(II) ions.

Describe a chemical test which can be used to identify the metal ions
present in the colourless solution and describe the expected observations.

 

 

 

 




Answer:

(a)(i) A: H2SO4
B: Na2SO4
C: Fe(OH)3
M: Fe

(ii) Fe2+(aq) + 2OH(aq) –> Fe(OH)2(s)

(b) Add hydrochloric acid/ sulfuric acid/ aq. potassium iodide. / any aqueous solution           of chloride or sulfate. Hydrochloric acid/sulfuric acid: white ppt forms if lead(II) ion       present; no visible reaction for aluminium ion. Aq. potassium iodide: yellow ppt             forms if lead(II) ion present; no visible reaction for aluminium ion.

Qualitative Analysis Revision MCQ Questions

1.    Which compound in solution produces a precipitate with aqueous ammonia that does not dissolve when an excess of ammonia is added?

A    Copper(II) sulfate

B    Iron(II) chloride

C    Potassium hydroxide

D    Zinc Chloride


2.    Refer to the scheme below to identify the unknown.

QE Q2.PNG


3.    Solution X contains a simple salt. The table shows the results of some tests on solution X.QE Q3.PNGWhat is the name of the salt in solution X?

A    iron(II) chloride

B    iron(III) chloride

C    iron(II) sulfate

D    iron(III) sulfate


4.    Refer to the scheme below to identify the unknown.

QE Q4.PNGWhich of the following could be solid X?

                Solid X                                        Gas Z
A    Sodium hydroxide                     Water vapour
B    Calcium hydroxide                    Water vapour
C           Zinc nitrate                              Ammonia
D    Aluminium nitrate                       Ammonia


5.    When aqueous sodium hydroxide is added dropwise until in excess to an unknown salt solution, a green precipitate is formed and is insoluble in excess aqueous sodium hydroxide. The precipitate turns brown slowly.
Which of the following is the unknown salt?

A    copper(II) sulfate

B    iron(II) sulfate

C    iron(III) sulfate

D    lead(II) sulfate


6.    When heated, solid P gives off a gas which forms a white precipitate with limewater. The residue reacts with dilute acid and also with aqueous alkali. What is P?
A    copper(II) carbonate

B    zinc carbonate

C    zinc oxide

D    copper(II) oxide


7.    1 cm3 of solution Q was added into two separate test tubes.

To one of the test tubes, an excess of aqueous sodium hydroxide was added
gradually. White precipitate which was soluble in excess aqueous sodium hydroxide was obtained.

To the other test tube, an excess of aqueous ammonia was added gradually.

White precipitate which was insoluble in excess aqueous ammonia was obtained.

What could solution Q contain?

A    lead(II) chloride

B    aluminium chloride

C    calcium chloride

D    ammonium chloride


8.    In a qualitative analysis, reagent M is gradually added to a salt solution N (that contains either 1 anion or 2 different anions), followed by the addition of dilute acid. The graph shows how the mass of precipitate formed changes with the reagents added.

QE Q8a.PNG

Which of the following combinations would produce the given results?

QE Q8b.PNG




Answer:

1.    B

2.    C

3.    C

4.    D

5.    B

6.    B

7.    B

8.    C