3. Identify each of the following observations as evidence of either a physical change or a chemical change.
(a) A piece of copper is heated until it melts.
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(b) A piece of aluminum corrodes in a solution of acid.​

If you add 10ml of hot water to 10ml of cold water and the change in tempature 8°c calculate how much energy is gained by the cold water

What is the polyatamic ion of borate

Ill give brainiestif one neutron initiates a fission event that produces two neutrons in the products, how many new reactions can now be initiated? if each of the neutrons produced in the first fission event then initiates a fission event that produces one neutron in the products, how many new reactions can now be initiated by each neutron? how many neutrons in total were produced by the two fission events described?