Add gelatin and let it boil, then put it in the freezer for 30 minuets
If the value of H is positive, it means you have to add that much heat to complete the reaction. If H is negative, it means that much heat is released during the chemical process. Because it is -73 kJ, 73 kJ of heat are released in the reaction.
Technically, the answer is iron. Oxygen has a melting point way below zero (-219 degrees celsius), ice becomes water AT room temperature and bromine is already a liquid at room temperature. So, iron has a melting point greater than room temperature due to the fact that metals are made up of giant structures of atoms in a regular arrangement, and there are strong forces of electrostatic attraction between positive metal ions and negative electrons, meaning that a lot of heat energy is required to break the bonds, i.e. a very high melting point, approx. 1500 degrees celsius. Hope this helps.
