How much heat energy is lost by any 50.0 g piece of copper when it cools from 95°C to 20°C

Explain why pure hydrogen cyanide does not conduct electricity, but become a conductor when it is dissolved in water? (at room temp, pure hcn exists as a volatile liquid)

What is the main reason why some developing countries fear the increase the free trade policies around the world?

What do electromagnetic waves carry? how are they produced through which media can they move? where do they transfer energy? what do they not transfer? what do mechanical waves carry? how are they produced? through which media can they move? where do they transfer energy? what do they not transfer?