Element, Compound & Mixture — Homi Bhabha Class 9 Chemistry MCQs with Solutions
Free Homi Bhabha Class 9 Chemistry Element, Compound & Mixture MCQs with step-by-step solutions (10 questions). Part of Matter & Its States. Practise online on Prepizo — no login needed.
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Questions with solutions
Q1 — Element, Compound & Mixture · medium · theory
A pure substance made up of only one kind of atom is called an:
A. compound
B. element ✓ Correct
C. mixture
D. alloy
Solution: An element consists of just one type of atom (e.g. oxygen, gold).
Q2 — Element, Compound & Mixture · hard · theory
A compound differs from a mixture because in a compound the components are:
A. physically mixed in any ratio
B. easily separated by filtration
C. chemically combined in a fixed ratio ✓ Correct
D. always metals
Solution: A compound has elements chemically bonded in a fixed proportion, with properties different from its constituents.
Q3 — Element, Compound & Mixture · medium · theory
Which of the following is a compound?
A. Air
B. Water ✓ Correct
C. Brass
D. Sea water
Solution: Water (H₂O) is a compound; air, brass and sea water are mixtures.
Q4 — Element, Compound & Mixture · medium · theory
Air is classified as a:
A. compound
B. pure substance
C. mixture ✓ Correct
D. element
Solution: Air is a mixture of gases (nitrogen, oxygen, etc.) in variable proportions.
Q5 — Element, Compound & Mixture · hard · theory
When iron and sulphur are heated together to form iron sulphide, the product:
A. can be separated by a magnet
B. is a mixture
C. has properties different from both iron and sulphur ✓ Correct
D. still behaves like iron and sulphur separately
Solution: Iron sulphide is a compound whose properties differ from those of iron and sulphur (which can no longer be magnetically separated).
Q6 — Element, Compound & Mixture · medium · theory
The components of a mixture can be separated by:
A. physical methods ✓ Correct
B. no method at all
C. only chemical reactions
D. only electrolysis
Solution: Mixtures can be separated by physical means (filtration, evaporation, etc.); compounds need chemical methods.
Q7 — Element, Compound & Mixture · easy · theory
Which one of the following is a compound?
A. Air
B. Oxygen
C. Brass
D. Water ✓ Correct
Solution: Water (H2O) is a compound made of hydrogen and oxygen combined in a fixed ratio. Oxygen is an element, while air and brass are mixtures.
Q8 — Element, Compound & Mixture · medium · theory
Which statement correctly distinguishes a compound from a mixture?
A. A compound can always be separated into its parts by simple physical methods
B. A mixture is always made of only one kind of atom
C. A mixture always has a fixed composition by mass
D. A compound has a fixed composition and properties different from its components, while a mixture does not ✓ Correct
Solution: A compound has a fixed composition and shows new properties, and its parts can be separated only by chemical means. A mixture has a variable composition and keeps the properties of its components.
Q9 — Element, Compound & Mixture · medium · theory
Iron filings and sulphur powder are mixed together and then heated strongly so that they form iron sulphide. Compared with the original mixture, the iron sulphide
A. still allows the iron to be picked out with a magnet
B. is a compound whose properties differ from both iron and sulphur ✓ Correct
C. has exactly the same yellow-grey colour and properties as the mixture
D. can easily be separated back by dissolving in carbon disulphide
Solution: Heating causes a chemical change forming iron sulphide, a new compound with properties unlike iron or sulphur; it is no longer attracted by a magnet and cannot be separated by physical methods.
Q10 — Element, Compound & Mixture · hard · numerical
Water always contains hydrogen and oxygen combined in the fixed mass ratio 1:8. When 36 g of water is completely decomposed, the masses of hydrogen and oxygen obtained are
A. 8 g of hydrogen and 28 g of oxygen
B. 18 g of hydrogen and 18 g of oxygen
C. 4 g of hydrogen and 32 g of oxygen ✓ Correct
D. 32 g of hydrogen and 4 g of oxygen
Solution: In the ratio 1:8 the total is 9 parts = 36 g, so 1 part = 4 g. Hydrogen = 1 x 4 = 4 g and oxygen = 8 x 4 = 32 g. This shows the fixed composition of a compound (law of constant proportions).