If we have equal masses of copper at 80oc and water at 20oc and we put them together, what is the final temperature?
a) pretty close to 50oc
b) pretty close to 80oc
c) pretty close to 20oc
d) greater than 80oc
e) less than 20oc

The final temperature will be close to 20°C

Explanation:

First of all, the resulting temperature of the mix can't be higher than the hot substance's (80°C) or lower than the cold one's (20°C). So options d) and e) are imposible.

Now, due to the high heat capacity of water (4,1813 J/mol*K) it can absorb a huge amount of heat without having a great increment in its temperature. On the other hand, copper have a small heat capacity (0,385 J/mol*K)in comparison.

In conclusion, the copper will release its heat decreasing importantly its temperature and the water will absorb that heat resulting in a small increment of temperature. So the final temperature will be close to 20°C

This analysis can be done because we have equal masses of both substances.

answer:

technetium is the most reactive. this is followed by silver. the least reactive out of these three elements is strontium.