Answer:
Complete each of the statements below. 
 
When work is done on a system by its surroundings, the sign of w is [ Select ] ["positive", "negative"] . 
 
When work is done by a system on its surroundings, the sign of w is [ Select ] ["negative", "positive"] . 
 
When q has a negative sign, we can say that heat is transferred [ Select ] ["from", "into"] the system [ Select ] ["from", "into"] its surroundings. 
 
If ∆U for a system is 0 and w is negative, then q must be [ Select ] ["positive", "negative"] . 
 
Explanation: