Water potential, how it is calculated and which direction water flows

Multiple choice by Anders Michael Nielsen, February 2020. Offline version w/o feedback here.
Video by Paul Anderson, also on his website Bozeman Science.

1
1
What is the water potential (ψ) of pure water?
2
2
Which direction does water flow?
3
1
What does the s in ψs stand for?
4
1
What does the p in ψp stand for?
5
1
What is the ionization constant of glucose?
6
2
What is the typical ψ of leaves?
7
1
What causes roots ψ to be negative?
8
2
Why is ψp in a leaf cell positive?
9
1
What does ψs equals?
10
1
What is the unit of the ionization constant?
11
3
What is the unit of the R constant?
12
3
How is Kelvin calculated from Celsius?
13
3
Open beaker, 0.4 M NaCl, 20 C … what is ψs?
14
1
Which Greek god makes it easier to remember ψs?
15
1
On which physical process is water movement based?