Freon-12, CF2Cl2, which has been widely used in air conditioning systems, is considered a threat to the ozone layer in the stratosphere. Calculate the root-mean-square velocity of Freon-12 molecules in the lower stratosphere where the temperature is –65°C.

The root mean squared velocity for CF2Cl2 is  

Explanation:

From the question we are told that

         The temperature is

Root Mean Square velocity is mathematically represented as

 Where  T is the temperature

              MW is the molecular weight of gas

              R is the gas constant with a value of  

For  CF2Cl2 its molecular weight is  0.121 kg/mol

     Substituting values

The velocity of freon-12 is 207.0998 m/s

Explanation:

The molar mass of freon-12=120.91g/mol=0.1209kg/mol

The root-mean-square velocity of Freon-12 is:

Where

R=8.31J/K mol

T=-65°C=208K

Replacing:

answer: c. the experiment shows that the red substance experienced a chemical change.

explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.

chemical changes are accompanied by following changes:

a) precipitate formation

b) energy is released or absorbed

c) formation of bubbles

d) change in color

as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.

e

smooth muscle is composed of involuntary muscles found within the walls of organs and structures such as the esophagus, stomach, intestines, and blood vessels. those muscles push materials like food or blood through organs. unlike skeletal muscle, smooth muscle can never be under your control.