Physical Properties of Metals and Non Metals - UNSOLVED PRACTICE SET

Q7. Define malleability and ductility. Give one example of a metal that shows each property.

Q8. List four physical properties of metals and four physical properties of non-metals.

Q9. Your school bell is made of metal, not wood or plastic. Explain why metals are preferred for making bells, using the property of sonority.

Q10. Why do metals generally have high densities while non-metals have low densities? Explain with examples.

Q11. Gold and silver are used for making jewellery. Explain the physical properties that make them suitable for this purpose.

Q12. Why is graphite (a form of carbon) used as a lubricant and in pencil leads, while diamond (also a form of carbon) is used in cutting tools? Explain the difference in their physical properties.

Q13. Describe the physical properties of metals and non-metals with examples. Explain the following properties in detail: (i) lustre, (ii) malleability, (iii) ductility, (iv) conductivity, and (v) sonority. Why do metals generally have these properties while non-metals do not? Give at least two exceptions for each category.

Q14. A student is given five samples: copper wire, sulphur powder, iron sheet, graphite rod, and iodine crystals. She is asked to classify them as metals or non-metals based on physical properties.

(a) How can she use appearance (lustre) to classify them?

(b) How can she test for malleability?

(c) How can she test for electrical conductivity?

(d) Which sample is likely to be the exception in its category, and why?

(e) Design a simple table to record her observations and conclusions.

Q15. "The physical properties of metals and non-metals determine their uses in our daily lives and industries." Discuss this statement by explaining:
(i) why aluminium is used for making aircraft bodies,
(ii) why copper is used for electrical wiring,
(iii) why graphite is used in pencils and as a lubricant, and
(iv) why mercury is used in thermometers despite being a metal.

Q16. A metal workshop uses various metals for different purposes. The densities of some metals are given below:

Table

Metal Density (g/cm³)

Aluminium 2.7

Iron 7.9

Copper 8.9

Silver 10.5

Gold 19.3

(a) If a jeweller makes a ring of volume 2 cm³ from gold, calculate the mass of the ring.

(b) An aircraft manufacturer needs a metal sheet of mass 540 kg. If the volume required is 200,000 cm³, which metal from the table is most suitable? Calculate its density and verify.

(c) A copper wire has a mass of 178 g. If the density of copper is 8.9 g/cm³, calculate the volume of the wire.

(d) Why is aluminium preferred over iron for making aircraft parts, even though iron is stronger?

(e) If a gold ornament weighs 38.6 g, what is its volume?

Q17. In a school laboratory, students compare the electrical conductivity of various materials.

(a) A copper wire of length 2 m and cross-sectional area 2 mm² carries a current of 5 A when connected to a 0.1 V source. Calculate the resistance of the wire. (R = V/I)

(b) A graphite rod of the same dimensions has a resistance 1000 times greater than copper. Calculate its resistance.

(c) Why is copper preferred over graphite for household wiring, despite graphite being cheaper?

(d) Silver has the highest electrical conductivity of all metals, yet it is not used for household wiring. Why?

(e) If aluminium is used instead of copper for overhead power lines, and aluminium has about 60% of copper's conductivity, how much thicker must the aluminium wire be to carry the same current? (Hint: Consider cross-sectional area)

Q18. A metallurgical company in India produces metals for various industries.

(a) The company produces aluminium sheets for the packaging industry. If a sheet has dimensions 100 cm × 50 cm × 0.05 cm, calculate its mass. (Density of Al = 2.7 g/cm³)

(b) The company also produces iron beams for construction. If a beam has a volume of 5000 cm³, calculate its mass. (Density of Fe = 7.9 g/cm³)

(c) Why is aluminium foil used for wrapping food instead of iron foil? Give two reasons based on physical properties.

(d) The company tests the malleability of gold by hammering it into a thin leaf. If 1 g of gold can be beaten into a leaf covering 1 m², calculate the thickness of the leaf. (Density of gold = 19.3 g/cm³, 1 m² = 10,000 cm²)

(e) Why is gold's extreme malleability both an advantage and a limitation for its use in jewellery?