Answer: It is true that Your friend should release the 
first.
Explanation:
The velocity of particles of a gas is inversely proportional to the mass of gas. This means that more is the mass of gas less will be its velocity.
Or, more will be the mass of gas more slowly it will move from one place to another.
The molar mass of chlorine gas is more than the molar mass of hydrogen gas. Therefore, chlorine gas will move slowly.
So, your friend should release the gas first and then according to the length of room you should release the 
gas.
Thus, we can conclude that it is true that Your friend should release the first.
Answer:
<h3>Sand cannot mixed on water not float on water .</h3>
<h3>When we mix sand and water , No reaction take place . The sand simply settles down at the bottom of the water container . This is why sand is heavier than water and therefore cannot float in water .</h3>
<h2>Hope this helps you ✌️</h2>
Ethanol C₂H₆O
Explanation:
When ethanol (CH₃-CH₂-OH) is heated in the presence of the sulphuric acid (H₂SO₄) it will produce ethylene (CH₂=CH₂ ) and water (H₂O).
CH₃-CH₂-OH → CH₂=CH₂ + H₂O
Learn more about:
sulphuric acid
brainly.com/question/867125
#learnwithBrainly
A controlled variable is the one that is kept constant, the manipulated variable is the independent variable in an experiment , it is called manipulated because is the one that can be changed. A responding variable or variables are the dependent variables that change as a result of the changes in the manipulated variable.
