Science
The following activity is set-up in the science lab by the teacher. He clamped an aluminium wire on a stand and fixed a pin to the free end of the wire using wax. Then he heated the wire with a burner from the end where the wire is clamped. Students observed the pin fall off.
(a) If the teacher replaces aluminium wire by silver wire, will the students’ observation change? Justify your answer.
(b) Will the aluminium wire melt? Give reason for your answer.
Answer
(a) The pin will drop but will take less time to drop because silver is a better conductor of heat than aluminium which means that heat will reach the waxed end faster, melting the wax sooner and causing the pin to fall quickly.
(b) No, the aluminium wire will not melt because metals have high melting points so the heat supplied by the burner is not enough to melt the aluminium; it only transfers along the wire to melt the wax.
Related Questions
In the reaction of aqueous solution of barium chloride with aqueous solution of sodium sulphate, the aqueous solution formed will be:
options
- BaCl2
- BaSO4
- Na2SO4
- NaCl
Assertion (A) : C4H8, C4H6 and C4H10 are members of the same homologous series.
Reason (R) : C4H8, C4H6, C3H4, C3H6, C2H4, C2H2 are unsaturated hydrocarbons.
options
- Both A and R are true, and R is the correct explanation of A.
- Both A and R are true, and R is not the correct explanation of A.
- A is true but R is false.
- A is false but R is true.
An element ‘X’ is stored in kerosene and cannot be extracted from its ore using a reducing agent. ‘X’ forms an ionic compound on reaction with chlorine.
(a) Can we store ‘X’ in water? Give reason to support your answer.
(b) Identify element ‘X’. Name the process used and write the equation for extraction of ‘X’ from its ore.
The domes of many building in Europe are made of copper. These domes now appear greenish in colour.
(a) Why do the domes appear greenish though copper is orange-red in colour?
(b) In your opinion, should the copper domes be replaced by iron domes to overcome the problem of change of colour of copper domes?
(c) Domes used to be made from thin sheets of metals. Why did the ancient architects use copper to make domes?