Which of the following is an exothermic process?

ice melting
boiling soup
water evaporating
condensation of water vapor
mixing ammonium thiocyanate and barium hydroxide and witnessing a temperature drop

I'm torn between ice melting and the last one.

You must add heat to melt ice? right? So that makes it endothermic. You must add heat to boil soup and evaporate water. That makes them endothermic. If you ADD heat to vaporize water, then heat is released when water vapor condenses; therefore, this must be exothermic.

Well, if you're torn between ice melting and the last one, I must say that mixing ammonium thiocyanate and barium hydroxide and witnessing a temperature drop definitely takes the cake! It's like a science version of a magic trick - poof, and the temperature drops! Just imagine, you mix those two together and the reaction is so cool, it literally leaves you feeling chilled. Quite the exothermic showstopper, I must say!

An exothermic process refers to a process that releases energy in the form of heat. Among the options you provided, both ice melting and the mixing of ammonium thiocyanate and barium hydroxide can be considered exothermic processes.

When ice melts, it absorbs heat from its surroundings to break the intermolecular bonds and change from a solid to a liquid state. This absorption of heat is an endothermic process.

On the other hand, when ammonium thiocyanate and barium hydroxide are mixed, they undergo a chemical reaction that releases heat. This release of heat indicates an exothermic process.

Therefore, the correct answer is the last one: mixing ammonium thiocyanate and barium hydroxide and witnessing a temperature drop.

To determine which process is exothermic, we need to understand the concept of exothermic reactions. An exothermic process or reaction releases heat into its surroundings. Let's analyze the given options to identify the exothermic process.

1. Ice melting: To determine if this process is exothermic or endothermic, we need to consider the heat transfer. When solid ice melts into liquid water, it absorbs heat from its surroundings. Therefore, the ice melting process is endothermic, not exothermic.

2. Boiling soup: Boiling is a phase change process where liquid transforms into gas. This process requires energy input, so it is endothermic.

3. Water evaporating: Similar to boiling, evaporation is another phase change process where a liquid transforms into a gas state. It also requires energy input, making it endothermic.

4. Condensation of water vapor: When water vapor condenses into liquid, it releases heat energy into its surroundings. This heat transfer makes the process exothermic.

5. Mixing ammonium thiocyanate and barium hydroxide: Mixing these two substances can cause an exothermic reaction. Since you mentioned witnessing a temperature drop, it suggests that heat is being released into the surroundings during the reaction. Therefore, this process is exothermic.

Based on the explanations above, the exothermic process among the options provided is the mixing of ammonium thiocyanate and barium hydroxide, which results in a temperature drop.