If it takes 41000 J of heat to melt 200.g of solid copper to liquid copper, what is the heat of fusion of copper?

An atom of sodium-23 (atomic number = 11) has a positive charge of +1. give this information, how many electrons does it have? how many proteins and neutrons does this atom have

Great amounts of electromagnetic energy from our sun and other bodies in space travel through space. which is a logical conclusion about these electromagnetic waves? their energy must be very their frequency must be very low these waves can travel without a medium they only travel through a vacuum of space

Under which circumstances are kp and kc equal for the reaction aa(g)+bb(g)⇌cc(g)+dd(g)?