1 W = 1 J/s
Therefore;
Total energy = 90*1*60*60 J = 324000 J = 324 kJ
Such an evaporation must take place at a temperature near the body temperature. Assuming a body temperature of 37°C at which heat of vaporization is approximately 2413.1 kJ/kg (again assuming sweet behaves like water).
Then,
mC = 324 kJ, where m = mass of sweet and C = heat of vaporization
Therefore,
m = 324/C = 324/2413.1 = 0.13427 kg
Density = m/v => volume = m/Density = 0.13427/1000 = 1.3427*10^-4 m^3
1 m^3 = 1000 liters
Then,
1.3427*10^-4 m^3 = 0.13427 liters of sweet = 134.27 ml
To solve this problem we will use the concepts related to the Impulse-Momentum Theorem for which it is specified as the product between force and change in time

And
\Delta p = m\Delta v
Where,




Rearranging to find the Force we have that

Using the expression between mass and velocity

Our values are given as,

Then replacing we have that

Therefore the average force is 6.99N
Result of the other variable
I suppose they can all be classified as compounds