Which of the following processes areEndothermic?
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)
a. C₂H₂OH(1)→ C₂H₂OH(g) - Endothermic (going from liquid to gas usually requires energy input)
b. Br₂(1)→→ Br₂(s) - Exothermic (going from gas to solid usually releases energy)
c. CH2(g) +802(g) → 5CO2(g) + 6H₂O(1) - Exothermic (production of CO2 and H2O usually releases energy)
d. NH3(g) →→→ NH₂(1) - Endothermic (breaking chemical bonds usually requires energy input)
e. NaCl(s)→→→ NaCl(1) - Endothermic (going from solid to liquid usually requires energy input)
To determine which of the processes are endothermic, we need to look at the change in enthalpy (∆H) for each process.
a. C₂H₂OH(1) → C₂H₂OH(g)
This process involves converting a liquid to a gas. Since the gas state is generally higher in energy than the liquid state, this process is endothermic.
b. Br₂(1) → Br₂(s)
This process involves converting a gas to a solid. Generally, the solid state is lower in energy than the gas state, so this process is exothermic.
c. CH2(g) + 802(g) → 5CO2(g) + 6H₂O(1)
This process involves the combustion of methane (CH4). Combustion reactions are usually highly exothermic, meaning they release energy. Therefore, this process is exothermic.
d. NH3(g) → NH₂(1)
This process involves the decomposition of ammonia. Typically, decomposition reactions require an input of energy, so this process is endothermic.
e. NaCl(s) → NaCl(1)
This process involves the dissolution of solid sodium chloride in water. Dissolution typically involves breaking the ionic bonds in the solid, which requires an input of energy. Therefore, this process is endothermic.
In summary, the endothermic processes are:
a. C₂H₂OH(1) → C₂H₂OH(g)
d. NH3(g) → NH₂(1)
e. NaCl(s) → NaCl(1)
To determine which processes are endothermic, we need to understand what endothermic means. An endothermic process is a process that absorbs heat from its surroundings. This means that the system gains heat while the surroundings lose heat.
To identify if a process is endothermic, one way is to look for a change in enthalpy (∆H). If ∆H is positive (greater than zero), it indicates that the process absorbs heat and is endothermic. If ∆H is negative (less than zero), it indicates that the process releases heat and is exothermic.
Now, let's analyze each process given and determine if they are endothermic:
a. C₂H₂OH(1) → C₂H₂OH(g)
We don't have information about whether heat is absorbed or released, so we cannot determine if it's endothermic based on the equation alone.
b. Br₂(1) → Br₂(s)
No enthalpy change is mentioned in the equation, so we cannot determine if it's endothermic based on the equation alone.
c. CH2(g) + 802(g) → 5CO2(g) + 6H2O(1)
Again, no information is given about the enthalpy change, so we cannot determine if it's endothermic based on the equation alone.
d. NH3(g) → NH₂(1)
Similarly, there is no information provided about the enthalpy change, so we cannot determine if it's endothermic based on the equation alone.
e. NaCl(s) → NaCl(1)
The transition from a solid to an aqueous solution is known as dissolution, and it generally requires energy. So, this process is likely to be endothermic.
In conclusion, based on the given information, the only process that is likely to be endothermic is process e, which is the dissolution of NaCl(s) into NaCl in solution. For the other processes, we don't have enough information to determine if they are endothermic or not.