Differences - Mixtures vs Compounds - UNSOLVED PRACTICE SET
Chapter: Is Matter Around Us Pure | Topic: Differences Mixtures vs Compounds
DIFFERENCES - MIXTURES VS COMPOUNDS - UNSOLVED PRACTICE SET
Topic: Differences Mixtures vs Compounds
Multiple Choice Questions
Q1. Which of the following is a key difference between a mixture and a compound?
- Mixtures are always liquids, compounds are always solids
- Mixtures can be separated by physical methods, compounds require chemical methods
- Compounds have variable composition, mixtures have fixed composition
- Mixtures are pure substances, compounds are impure
Q2. Air is a mixture, while water is a compound. This is because:
- Air is a gas and water is a liquid
- Air has variable composition, while water has fixed composition
- Air is colourless, while water is colourless too
- Air contains oxygen, while water does not
Q3. Which property is common to both mixtures and compounds?
- Fixed melting point
- Can be separated by physical methods
- Made up of two or more substances
- Formed by chemical reaction only
Q4. A mixture of hydrogen and oxygen gases can be separated by:
- Electrolysis
- Filtration
- Using a magnet
- Simple physical methods like diffusion
Q5. Which statement correctly describes the energy change during the formation of a compound?
- No energy change occurs
- Energy is always released
- Energy is either absorbed or released
- Energy is always absorbed
Q6. Brass (copper + zinc) is a mixture, while copper sulphate (CuSO₄) is a compound. The main difference is that:
- Brass is yellow, copper sulphate is blue
- Brass can be separated by physical methods, while copper sulphate requires chemical decomposition
- Brass is expensive, copper sulphate is cheap
- Brass is used in jewellery, copper sulphate is not
Short Answer Questions
Q7. List any four differences between a mixture and a compound.
Q8. Why does a compound have a fixed melting point, while a mixture does not? Explain with reference to the arrangement and bonding of particles.
Q9. Your father uses a mixture of petrol and air in his car engine. Is this mixture a compound? Give two reasons to support your answer.
Q10. "The properties of a compound are completely different from the properties of its constituent elements." Give one example to illustrate this statement.
Q11. A student has a sample that can be separated into its components by simple filtration. Can the sample be a compound? Explain your reasoning.
Q12. Compare a mixture of iron and sulphur with the compound iron sulphide on the basis of:
(i) effect of a magnet,
(ii) action of dilute acid, and
(iii) melting point.
Long Answer Questions
Q13. Prepare a comprehensive comparison table highlighting at least six differences between mixtures and compounds. For each difference, provide a clear example to illustrate your point. Explain why these differences arise at the molecular level.
Q14. A teacher presents two black powders to the class — Powder P and Powder Q. Powder P is attracted by a magnet, and when dilute HCl is added, a gas with a rotten egg smell is produced. Powder Q is not attracted by a magnet, and when dilute HCl is added, no gas is produced.
(a) Identify Powder P and Powder Q.
(b) Is Powder P a mixture or a compound? Justify.
(c) Is Powder Q a mixture or a compound? Justify.
(d) Write the chemical equation for the reaction of Powder P with dilute HCl.
(e) What would happen if Powder Q is heated strongly with iron filings?
Q15. "Understanding the difference between mixtures and compounds is fundamental to chemistry and has practical implications in industry and daily life." Discuss this statement by giving three examples from: (i) the food industry, (ii) the pharmaceutical industry, and (iii) construction materials. In each example, explain whether a mixture or a compound is used and why.
Numerical / Application-Based Problems
Q16. A student is given two samples:
Sample A: 10 g of a mixture of iron filings and sulphur powder (ratio 7:3 by mass)
Sample B: 10 g of iron sulphide (FeS)
(a) Calculate the mass of iron and sulphur in Sample A.
(b) When both samples are treated with carbon disulphide, what happens to each? Explain.
(c) When both samples are treated with a magnet, what happens to each? Explain.
(d) Calculate the mass percentage of iron in iron sulphide (FeS). (Atomic masses: Fe = 56, S = 32)
(e) Compare the mass percentage of iron in Sample A and Sample B.
Q17. A factory produces two types of materials:
Material X: An alloy of copper and zinc (brass) containing 70% copper and 30% zinc by mass
Material Y: A compound formed by the reaction of copper and sulphur (copper sulphide, Cu₂S)
(a) If the factory produces 500 kg of Material X, calculate the mass of copper and zinc used.
(b) Calculate the mass percentage of copper in Cu₂S. (Atomic masses: Cu = 63.5, S = 32)
(c) If 200 kg of copper reacts completely with sulphur to form Cu₂S, calculate the mass of Cu₂S produced and the mass of sulphur required.
(d) Why is Material X called a mixture while Material Y is called a compound, even though both contain copper?
Q18. In a school laboratory, a teacher prepares two beakers:
Beaker 1: 50 g of sugar dissolved in 150 g of water
Beaker 2: 50 g of calcium oxide (CaO) added to 150 g of water — a chemical reaction occurs, forming calcium hydroxide (Ca(OH)₂)
(a) Is the contents of Beaker 1 a mixture or a compound? Justify.
(b) Is the contents of Beaker 2 a mixture or a compound? Justify.
(c) Calculate the mass percentage of sugar in Beaker 1.
(d) If the reaction in Beaker 2 follows the equation CaO + H₂O → Ca(OH)₂, and 50 g of CaO reacts with 18 g of water, calculate the mass of Ca(OH)₂ formed and the mass of unreacted water.
(e) Can the contents of Beaker 1 be separated by evaporation? Can the contents of Beaker 2 be separated by evaporation? Explain.