Which of the following processes are Endothermic?
a. C₂H₂OH(1)→ C₂H₂OH(g)
b. Br₂(1)→→ Br₂(s)
c. CH2(g) +802(g) → 5CO2(g) + 6H₂O(1)
d. NH3(g) →→→ NH₂(1)
e. NaCl(s)→→→ NaCl(1)
b. Br₂(1)→→ Br₂(s)
d. NH3(g) →→→ NH₂(1)
To identify if a process is endothermic, we need to determine if the process absorbs or releases heat. Here are the steps to determine if each of the processes listed is endothermic:
a. C₂H₂OH(1) → C₂H₂OH(g)
In this process, a liquid (C₂H₂OH(1)) is converted into a gas (C₂H₂OH(g)). Converting a substance from a liquid to a gas typically requires absorbing heat from the surroundings, so this process is endothermic.
b. Br₂(1) → Br₂(s)
This process involves the conversion of the vapor Br₂(1) into a solid Br₂(s). The conversion from vapor to solid releases heat as the molecules come closer together, so this process is exothermic.
c. CH2(g) +802(g) → 5CO2(g) + 6H₂O(1)
This equation represents the combustion of methane (CH4) to produce carbon dioxide and water. Combustion reactions are typically exothermic because they release heat when fuels react with oxygen. In this case, the reaction releases heat, so it is exothermic.
d. NH3(g) → NH₂(1)
This process involves the conversion of ammonia gas (NH3(g)) to ammonia anion (NH₂(1)). The conversion from gas to solid typically releases heat as the particles come closer together, so this process is exothermic.
e. NaCl(s) → NaCl(1)
This process represents the conversion of solid NaCl into ionic NaCl in the aqueous phase (dissolving in water). Dissolving ionic substances in water is an endothermic process because it requires energy to overcome the attraction between the ions in the solid lattice. Therefore, this process is endothermic.
In summary, the endothermic processes are:
a. C₂H₂OH(1) → C₂H₂OH(g)
e. NaCl(s) → NaCl(1)
To determine which of the processes are endothermic, we need to understand what endothermic means. Endothermic refers to a process or reaction that absorbs heat from its surroundings. In other words, it requires an input of energy in the form of heat to proceed.
Now, let's evaluate each of the given processes:
a. C₂H₂OH(1)→ C₂H₂OH(g)
This process involves converting a liquid substance (C₂H₂OH) into a gaseous state (C₂H₂OH). Usually, the transition from a liquid to a gas requires an input of energy to overcome intermolecular forces. Consequently, this process is endothermic.
b. Br₂(1)→→ Br₂(s)
This process entails the conversion of gaseous bromine (Br₂) into a solid state (Br₂). When a gas transforms into a solid, energy is released as heat. Therefore, this process is exothermic, not endothermic.
c. CH2(g) + 802(g) → 5CO2(g) + 6H₂O(1)
From the given chemical equation, we cannot directly determine the enthalpy change (heat absorbed or released) of the reaction. To identify if it is endothermic or exothermic, we would need to know the enthalpy values of the individual substances involved. Without that information, we cannot definitively say whether this process is endothermic or exothermic.
d. NH3(g) →→→ NH₂(1)
Similar to the previous case, without specific enthalpy values, we cannot determine if this process is endothermic or exothermic.
e. NaCl(s)→→→ NaCl(1)
This process represents the dissolution of solid NaCl into an aqueous solution (NaCl in water). The dissolution of ionic compounds like NaCl usually involves the breaking of ionic bonds, which requires an input of energy. Therefore, this process is endothermic.
In summary, the processes that are endothermic are:
a. C₂H₂OH(1) → C₂H₂OH(g)
e. NaCl(s) → NaCl(1)