Answer:
1 mole of H2O is 18 grams (2 g H + 16 g Oxygen)
36 / 18 = 2
So 2 moles = 2 * 6.02E23 = 12.04E23 = 1.204E24
3 is the answer to your question
Impulse = Ft = (m)(delta v)
delta v = change in velocity = velocity final - velocity initial.
= -22m/s - +18m/s = -40m/s.
mdeltav = (0.40kg)(-40m/s) = -16kgm/s or -16Ns.
The vector, the x-component and the y-component form a rectangle triangle where the vector is the hypothenuse and the x and y components are the two sides.
Calling

the angle between the vector and the horizontal direction (x), the two sides are related to

by

where vy and vx are the two components on the y- and x-axis. Using vx=10 and vy=3 we find

And so the angle is