Answer:
Amount of frozen soup = 2500 mL
Explanation:
We are told that tom made 5,000 mL of soup. 
We are also told he packed 2.5 Litres into his kids' lunches. 
Now, from conversions, 
1 liter = 1000 mL
Thus, 
2.5 litres = 2.5 × 1000 = 2500 mL
Now, we are told he froze the rest of the soup. 
Thus;
Amount of frozen soup = total amount of soup made - amount given to kids' lunch pack. 
Amount of frozen soup = 
5000 - 2500 = 2500 ml