Which of the following is NOT a spontaneous reaction?
a. Ice melting at 25 °C under atmospheric pressure
b. Water freezing at 25 °C under atmospheric pressure
c. Two gases mixing in the same container
d. A gas expanding into a larger volume container
e. A hot object warming up a colder object in contact with it
My answer was e but it is wrong, so I'm now thinking it would be b but it says under atmospheric pressure which leads me to think it's spontaneous. I'm so confused can someone help. Thanks
does water spontaneously freeze outside in the summer?
... that is basically what b is saying
Oh darn I'm an idiot haha Thanks for clarifying that
I'd be happy to help clarify your confusion. To determine which of the options is NOT a spontaneous reaction, we can consider the concept of spontaneous processes and the conditions under which they occur.
A spontaneous reaction or process is a change that occurs without the input of external energy or intervention. In other words, it occurs naturally and proceeds on its own without needing to be forced or driven by an external force.
Now, let's analyze each option to determine whether it is a spontaneous reaction:
a. Ice melting at 25 °C under atmospheric pressure:
This is a spontaneous reaction because at a temperature above its melting point, ice naturally melts into water without requiring any external input.
b. Water freezing at 25 °C under atmospheric pressure:
This process is NOT a spontaneous reaction. At temperatures above its freezing point, water naturally remains in its liquid form. Hence, in this case, freezing of water would require external energy input to bring it below its freezing point.
c. Two gases mixing in the same container:
This is a spontaneous reaction. When two gases are combined in the same container, they will mix and distribute evenly throughout the container due to the random motion of gas molecules (diffusion).
d. A gas expanding into a larger volume container:
This is also a spontaneous reaction. When a gas expands into a larger volume container, it does so due to the tendency of gas molecules to spread out and occupy a larger space. This is in line with the concept of increased entropy, which favors spontaneous processes.
e. A hot object warming up a colder object in contact with it:
Contrary to your initial intuition, this is indeed a spontaneous reaction. Heat transfer from a hotter object to a colder object is a spontaneous process as energy flows naturally from higher to lower temperatures until thermal equilibrium is achieved.
Based on the above analysis, the correct answer to the question "Which of the following is NOT a spontaneous reaction?" would be option b: Water freezing at 25 °C under atmospheric pressure, as it requires external energy input to occur.
It is common for concepts to be confusing at times, and it's great that you sought clarification. Feel free to ask any further questions if needed!