One of the critical properties of polymers is elasticity. The ability of many polymeric materials to be stressed and deformed but return to their original shape is a characteristic that is often valuable to engineers. Suggest a reason why polymer molecules are mostly elastic.Required to answer. Single choice.

a made of amorphous solid

b made of metallic solid

c made of crystalline solid

d made of ionic solid

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When Pt and Co are electrically connected, which will not be corroded?

a Both will corrode at the same rate

b None

c Co

d Pt

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Which of the following statements is NOT true?Required to answer. Single choice.

a High carbon steels are tougher than low carbon steel.

b Galvanized iron is essentially iron that has been coated with protective zinc layer.

c Stainless steel and aluminum are both self-passivating materials, but they are not impervious to corrosion.

d Alkali carbonates are more reactive than alkaline earth metals.

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A zinc bar weighing 3.0 kg is attached to a buried iron pipe to protect the pipe from corrosion. An average current of 0.020 A flows between the bar and the pipe. How many years will be required for the zinc bar to be entirely consumed?

a 600 yrs

b 5.99 yrs

c 14.0 yrs

d 7.00 yrs