1 is D - double-replacements do not make solid metals
2 is A - to have complete combustion the original compound must ONLY have C, H and O
3 is B - the elemental Mg replaces the H in the HCl
Energy is invisible yet it's all around us and throughout the universe. Energy can never be made or destroyed, but its form can be converted and changed.
While energy can be transferred or transformed, the total amount of energy does not change – this is called energy conservation.
Energy transformation, also known as energy conversion, is the process of changing energy from one form to another. In physics, energy is a quantity that provides the capacity to perform work or provides heat.
When energy is transformed from one form to another, or moved from one place to another, or from one system to another there is energy loss. This means that when energy is converted to a different form, some of the input energy is turned into a highly disordered form of energy, like heat. This consent is known as “hidden energy”.
All i know is that #7 is true