CIE iGCSE Co-Ordinated Science C9.1 Properties of metals Exam Style Questions Paper 4
Question
Fig. 9.1 shows two identical infrared heating lamps that are heating two metal cubes. The lamps
are at the same distance from the cubes. The lamps are heating each cube for the same time.
One lamp is heating the dull white metal cube and the other the dull black metal cube.
(a) (i) Explain why the temperature of the dull black cube rises more than the temperature of
the dull white cube.
(ii) The dull black metal cube is replaced by a shiny black metal cube.
Explain why the temperature of the shiny black cube rises less than the temperature of
the dull black cube.
(iii) Infrared radiation emitted by the lamps includes radiation with a wavelength of 0.75mm.
Calculate the frequency of this infrared radiation.
frequency = ……………………………………………. Hz
(iv) Thermal energy is conducted through the metal cubes.
Describe the process of conduction in a metal.
(b) One of the cubes is now filled with hot water. A student uses a digital thermometer containing
a thermocouple to measure the temperature of the water inside the cube.
(i) Describe the structure of a thermocouple used to measure temperature.
(ii) The thermocouple produces an electromotive force (e.m.f.).
Place ticks (✓) in Table 9.1 to compare e.m.f. to potential difference.
▶️Answer/Explanation
Ans : 9(a)(i) dull black (cube) absorbs (thermal / infrared) radiation better than dull white (cube) ; 9(a)(ii) shiny black (cube) reflects radiation (rather than absorbs as the dull surface of black cube does) ;
9(a)(iii) use of 3.0 × 108
(m / s) ;
(f =) v / λ / 3.0 × 108
/ 0.75 × 10–3
;
(f =) 4.0 × 1011 (Hz) ;
9(a)(iv) vibrations (of ions / atoms) ;
passes from one ion / atom to the next ;
also by electrons moving through metal ;
9(b)(i) two different metal wires joined at two junctions at different temperatures ;
9(b)(ii) electromotive force and potential difference ticked ;
electromotive force and potential difference ticked ;
electromotive force only ticked ;
Question
This question is about metals.
(a) Aluminium is used to make aircraft.
Identify from the list below one property of aluminium that makes it suitable for this purpose.
(b) Aluminium is used to make food containers because it is resistant to corrosion.
Explain why aluminium is resistant to corrosion.
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(c) Metals can be mixed with other elements to form alloys.
Fig. 2.1 shows the structures of pure aluminium and an alloy of aluminium.
An alloy of aluminium called duralumin is often used to make aircraft instead of pure aluminium.
Explain, in terms of their structures and properties, why the alloy is used instead of pure aluminium.
…………………………………………………………………………………………………………………………………
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(d) Steel is an alloy of iron. Steel is used to make car bodies.
The steel is usually coated with zinc before it is painted.
The zinc prevents rusting, even if the zinc layer is damaged.
Describe how the zinc prevents rusting.
…………………………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………………………
(e) Table 2.1 shows a reactivity series for some metals.
Carbon, a non-metal, is also shown in Table 2.1.
State a metal from Table 2.1 that is extracted from its ore by electrolysis.
Explain your answer.
metal ………………………………………..
explanation ……………………………………………………………………………………………………………….
…………………………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………………………
▶️Answer/Explanation
Ans: 2(a) low density ✓ ;
2(b) (aluminium) forms an oxide layer / reacts with oxygen / forms a layer of aluminium oxide ;
idea that the (oxide) layer adheres to the surface of the aluminium ;
2(c) explanation about alloy linking any three from:
added atoms are different size / atoms or ions in an alloy are different sizes / irregular arrangement ;
layers / particles cannot easily slide over each other ;
more energy is needed to cause slippage of the layers / owtte ;
idea that alloy is stronger ;
2(d) zinc is more reactive than iron / ORA ;
idea that zinc corrodes or oxidises or reacts instead of the iron ;
2(e) metal – sodium / calcium / magnesium ;
explanation
idea that the chosen metal is more reactive than carbon ;
idea that metal cannot be displaced from its ore by (heating with) carbon ;