Answer:
A spontaneous reaction is taking place in a flask. When you touch the flask, it feels cold and gets colder as the reaction progresses........(c,f,g)
A spontaneous reaction is taking place in a flask as evidenced by the formation of gas bubbles. When you touch the flask, it feels hot and gets hotter as the reaction progresses.... (c,d,h)
A spontaneous reaction is taking place in a flask. When you touch the flask, it feels hot and gets hotter as the reaction progresses....(c,f,h)
A spontaneous reaction is taking place in a flask. You notice the formation of gas bubbles intensifies as the reaction progresses....(c,d,I)
A solid in a closed flask begins to melt. (You can consider this a phase change.)....(b,d,g)
A liquid begins to appear on the inside of a closed flask. At first glance before the liquid began to appear, you might have thought the flask was empty. (You can consider this a phase change.)....(a,e,h)
Explanation:
Now it is necessary here to state the equation for ∆G
∆G= ∆H-T∆S
The values of ∆G depends on the relative values of ∆H, T and ∆S.
When heat is evolved by a system, ∆H is negative, when heat is absorbed by a system, ∆H is positive.
When gases are evolved, ∆S is positive, when gases turn to liquids or solids ∆S is negative.
Let us also recall that, for the melting process ∆S positive ( solid changes to liquid), ∆H is positive(energy is absorbed) and T increases( the substance is heated). Hence ∆G is negative
For the condensation process; ∆H is negative (heat is evolved), ∆S is negative (gas changes to liquid) and T is decreased hence ∆G is positive.
