which of the following sets correctly describes the signs of q and w respectively for the following exothermic process at p=1 atm and t=370 K? H20(g)=> H20(l)
a.) -,+
b.)+,-
c.)-,-
d.)+,+
e.) q and w are both zero
To determine the signs of q and w for the given exothermic process, we need to consider the definitions of q (heat) and w (work) and how they relate to the process.
1. Heat (q): In an exothermic process, heat is released from the system into the surroundings. As a result, q will be negative (since heat is leaving the system).
2. Work (w): Work can be done either on the system or by the system. In this case, we have the conversion of water vapor (H2O(g)) to liquid water (H2O(l)). The volume of water decreases, meaning work is done by the system on the surroundings. Since work is done by the system, w will be negative.
Now let's analyze each option:
a.) -,+ (q is negative, w is positive): This set doesn't correctly describe an exothermic process. The signs of q and w should both be negative for an exothermic process.
b.) +,- (q is positive, w is negative): This set doesn't correctly describe an exothermic process. The signs of q and w should both be negative for an exothermic process.
c.) -,- (q is negative, w is negative): This set correctly describes the signs of q and w for the exothermic process. The negative sign indicates that both q and w are negative, which is consistent with an exothermic reaction.
d.) +,+ (q is positive, w is positive): This set doesn't correctly describe an exothermic process. The signs of q and w should both be negative for an exothermic process.
e.) q and w are both zero: This set doesn't correctly describe an exothermic process. In an exothermic process, heat is released (q < 0) and work is done by the system (w < 0).
Therefore, the correct answer is c.) -,-, where both q and w are negative.