Which of the following processes are exothermic?
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)
The exothermic processes are:
b. Br₂(1) → Br₂(s)
c. CH₂(g) + 802(g) → 5CO₂(g) + 6H₂O(1)
e. NaCl(s) → NaCl(1)
To determine which processes are exothermic, we need to look for changes in enthalpy (ΔH) in the reactions. An exothermic process releases heat and has a negative ΔH value. Let's examine each process:
a. C₂H₂OH(1) → C₂H₂OH(g)
This process involves a change from a liquid to a gas. Generally, this type of change requires the input of energy, indicating an endothermic process. Therefore, this reaction is NOT exothermic.
b. Br₂(1) → Br₂(s)
This process involves a change from a gas to a solid state. The formation of a solid usually results in the release of energy, indicating an exothermic process. Therefore, this reaction is exothermic.
c. CH2(g) + 802(g) → 5CO2(g) + 6H₂O(1)
This process involves the combustion of methane (CH4) to produce carbon dioxide (CO2) and water (H2O). Combustion reactions are typically highly exothermic, as they release a large amount of energy. Therefore, this reaction is exothermic.
d. NH3(g) → NH₂(1)
This process involves the deprotonation of ammonia (NH3). Without more information about the reaction conditions, it is not possible to determine whether it is exothermic or endothermic.
e. NaCl(s) → NaCl(1)
This process involves a change from a solid to a gaseous state, which usually requires the input of energy, indicating an endothermic process. Therefore, this reaction is NOT exothermic.
In summary, the exothermic processes in the given options are:
- Br₂(1) → Br₂(s)
- CH2(g) + 802(g) → 5CO2(g) + 6H₂O(1)
To determine which of the processes are exothermic, we need to understand what exothermic means. In chemistry, an exothermic reaction or process is one that releases heat to its surroundings. In other words, it is a process that gives off heat energy.
Now let's analyze each of the given processes:
a. C₂H₂OH(1)→ C₂H₂OH(g)
Since the state changes from liquid to gas, this process requires energy to overcome the intermolecular forces holding the liquid together. Therefore, this process is endothermic, not exothermic.
b. Br₂(1)→→ Br₂(s)
In this process, the state changes from gas to solid. The formation of solid Br₂ releases energy in the form of heat, making it an exothermic process.
c. CH2(g) + 802(g) → 5CO2(g) + 6H₂O(1)
This chemical equation represents the combustion of methane (CH4). Combustion reactions typically release a large amount of energy in the form of heat and light. Therefore, this process is exothermic.
d. NH3(g) →→→ NH₂(1)
This process involves the decomposition of ammonia (NH3). To break the bonds holding the ammonia molecule together, energy is required, making this a endothermic process.
e. NaCl(s)→→→ NaCl(1)
This process represents the dissolution of solid sodium chloride (NaCl) in water. When an ionic compound dissolves in water, it releases energy in the form of heat. Therefore, this process is exothermic.
In conclusion, the exothermic processes among the given options are:
b. Br₂(1)→→ Br₂(s)
c. CH2(g) + 802(g) → 5CO2(g) + 6H₂O(1)
e. NaCl(s)→→→ NaCl(1)