Which of the following processes are endothermic? ice forming on a pond iodine crystals subliming water boiling gasoline burning
multiple answers

The boiling of water and sublimation of iodine crystals are endothermic processes.

Option B & C

Explanation:

Endothermic process are the classifications of chemical reactions where the heat is absorbed by the system from the surroundings. As the matters can exists in three phases like solid, liquid and gases.

The endothermic process occurs by absorption of heat energy by the system. So according to the given options, the boiling of water and iodine crystal sublimation follows endothermic process. In the boiling of water occurs when the water molecules absorb heat from the surrounding and convert to gas phase.

Similarly, the sublimation of iodine crystals also require heat energy from the surrounding to break the bonds of the iodine crystals to sublimate to gas phase. Thus the boiling of water and sublimation of iodine crystals are the examples of endothermic processes.

vanderwaal's forces of attraction are the electrostatic intermolecular forces that exist in a molecule due to the temporary or permanent dipoles that are developed in a molecule. in , the major intermolecular forces are dipole-dipole interactions as the molecule is polar (bent structure). so the vanderwaal's forces of interaction in between molecules are the permanent dipole-dipole interactions that develop due to the dipole that exists in between the polar h - s bond. the positively charged hydrogen atom is attracted towards the negative end of the dipole that is sulfur of the adjacent molecule. therefore, these forces of attraction are relatively stronger than that of london dispersion forces that exist in non polar molecules.

answer is: c. the experiment shows that the red substance experienced a chemical change.

this is chemical change (chemical reaction), because two new substances are formed (metalig liquid and gas), the atoms are rearranged and the reaction is followed by an energy change.

this is example of chemical decomposition.

chemical decomposition (analysis) is the separation of a single chemical compound into its two or more elemental parts or to simpler compounds.  

chemical decomposition is opposite of chemical synthesis.