The answer is vaporization, then condensation.
Here is a set of flash card that can help with this subject.
Complete Question
The complete question is shown on the first uploaded image
Answer:
a
The torque produced by the pile of rocks is
b
The distance of the single for equilibrium to occur is
Explanation:
From the question we are told that
The mass of the left rock is 
The mass of the rock on the right 
The distance from fulcrum to the center of the pile of rocks is 
Generally the torque produced by the pile of rock is mathematically represented as

Substituting values
Generally we can mathematically evaluated the distance of the the single rock that would put the system in equilibrium as follows
The torque due to the single rock is

At equilibrium the both torque are equal

Making
the subject of the formula

Substituting values
Answer:
<h2>
44 m/s</h2>
Explanation:
In this problem we are expected to calculate the velocity of Georges movements.
Given data
Total distance covered by George= 850+250= 1100 meters
Time taken by George to cover the total distance= 25 seconds
We know that velocity is, v= distance/ time
Therefore substituting our data into the expression for velocity we have
v= 1100/ 25= 44 m/s
Hence the velocity in m/s is 44
Chlorine gas or just chlorine?