Agas expands when 606 j of energy is added to it as heat. the expanding gas does 418 j of work on its surroundings. a. what is the overall change in the internal energy of the gas? b. if the work done by the gas were equal to 1212 j (rather than 418 j)

A)
 Q=606 J 
 W = 418 J 
 From first law of thermodynamics, 
 [ Uf - Ui ] = Q - W 
 [ Uf - Ui ]=606 -418=188 J 
 [ Uf - Ui ]= 188 J 
 
b )
 W2 = 1212 J 
 Q2 = ? 
 Ui2=Uf =Ui +188
 Uf2=Ui
 [ Uf2 - Ui2 ]=Ui-(Ui+188)
 -188 J 
 Q2=W2+(Uf2 -Uf1) 
 Q2 =1212 -188=1024 J 
 Q added in second step (b) so that internal energy is equal to initial internal energy of step (a)=1024 J

He sandals were out in the sun so the got hotter. which is why her feet felt hot.