MCQ's About "Atoms, Molecules, Mixtures, And Compounds".

ATOMS, MOLECULES, MIXTURES, AND COMPOUNDS

Question 1
Which of the following substances is an element?
(A)  coal  (B)  sand  (C)  petrol  (D)  diamond

Question 2
Metals:
(A)  make up more than three-quarters of all elements  (B)  never occur uncombined in nature
(C)  all rust or corrode  (D)  react vigorously with all non-metals
Question 3
Sulphur is an example of:
(A)  an element  (B)  a compound  (C)  a sulphide  (D)  a mixture

Question 4
Copper sulphate is an example of:
(A)  a mixture  (B)  an alloy  (C)  an element  (D)  a compound

Question 5
Water is a compound rather than an element because it:
(A)  is not easily broken down by heat  (B)  has a definite boiling point
(C)  is formed when hydrogen combines with oxygen  (D)  is a pure substance

Question 6
Carbon is an element rather than a compound because it:
(A)  is formed when wood is heated in air  (B)  has been known for many centuries
(C)  combines with oxygen to form a gas  (D)  cannot be broken down into two or more
substances

Question 7
Which of the following cannot be used to separate a mixture?
(A)  chromatography  (B)  sublimation  (C)  distillation  (D)  decomposition

Question 8
Two substances can be separated by distillation if they differ in:
(A)  solubility  (B)  melting point  (C)  boiling point   (D)  density

Question 9
Crude oil can be separated by fractional distillation because each fraction has a different:
(A)  composition  (B)  density  (C)  boiling point  (D)  melting point

Question 10

Chromatography is a:
(A)  method of separating chemically similar substances
(B)  process used to make photographic colour slides
(C)  process in which metal objects are coated with chromium
(D)  process for removing stains from paper during its manufacture

Question 11
A sample of ink is put in the centre of a circle of filter paper. Several drops of ethanol are then put on the ink
mark. Two concentric rings of colour are obtained. What is the best conclusion about the ink we can come
to?
(A)  It contains two coloured substances only.  (B)  It is a compound.
(C)  It contains at least two coloured substances.  (D)  It is broken down by ethanol.

Question 12
According to the scientist’s way of grouping or classifying substances, a substance must be either:
(A)  a solid or a liquid  (B)  an element, a compound, or a gas
(C)  a pure substance or a compound  (D)  an element, a compound, or a mixture

Question 13
If an element called X combines with another element called Y, to form a compound called XY, the properties
of XY will probably be:
(A)  similar to those of X  (B)  similar to those of Y
(C)  a mixture of the properties of X and Y  (D)  different from those of X or Y

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Answers:
Question 1

(D)  diamond
Question 2
(A)  make up more than three-quarters of all elements
Question 3
(A)  an element
Question 4
(D)  a compound
Question 5
(C)  is formed when hydrogen combines with oxygen
Question 6
(D)  cannot be broken down into two or more substances
Question 7
(D)  decomposition
Question 8
(C)  boiling point
Question 9
(C)  boiling point
Question 10
(A)  method of separating chemically similar substances
Question 11
(C)  It contains at least two coloured substances.
Question 12
(D)  an element, a compound, or a mixture
Question 13

(D)  different from those of X or Y