uhhhh idk cheif...
thats a big oof right there.
ged is always an option
Required Heat = Q
Q = Mass * specific heat of water * change in temp.
Q = 5g * 1g/cal*degC * 20degC
Q = 100 cal of heat is required
To convert calories to Joules,
1 cal = 4.184 Joules
100cal = 418.4 J of heat is needed