CHEM 121 EXAM PREP QUESTIONS ANSWERS STUDY GUIDE VERIFIED SOLUTION

CHEM 121 EXAM PREP QUESTIONS ANSWERS STUDY GUIDE VERIFIED SOLUTION
CHEM 121 Final EXAM Questions and Answers
Verified Solutions Latest Update 2026/2027

Question:
Property of Gases- 1

Answer:
assumes volume and shape



Question:
Property of Gases- 2

Answer:
compressible *KMT #1*



Question:
Property of Gases- 3

Answer:
density of gases<<liquids & solids; highly variable depending on temp.



Question:
Property of Gases- 4

Answer:
homogeneous mixtures (solutions) in any proportions b/c their molecules are far apart



Question:
Property of Gases- 5

Answer:

,volume of a gas occupies is inversely proportional to its pressure *V ~ 1/P* (volume of a weather
balloon increases as it ascends where pressure decreases)



Question:
Property of Gases- 6

Answer:
pressure in a rigid container is directly proportional to its absolute temperature *P ~ T* (low temps
set off low tire pressure)



Question:
Property of Gases- 7

Answer:
pressure inside a rigid container at constant temperature is directly proportional to the number of
moles of the gas in the container *P ~ n* (gauge of a scuba tank measures internal pressure to tell
how much air is left in the tank)



Question:
Parameters Affecting Gases

Answer:
-Pressure (P) Volume (V) Temperature (T) Number of Moles (n)



Question:
Effusion

Answer:
gas leaking from high pressure space to lower pressure space (balloon)



Question:
Graham's Law

,Answer:
rate of diffusion or effusion of a gas is inversely proportional to the square root of its molar mass:
*rate of effusion ~ (1/(sqrt(M))*



Question:
Graham's Law- Relative Rates of Effusion

Answer:




Question:
Kinetic Molecular Theory (KMT)

Answer:
explains WHY gases behave like the way they do



Question:
KMT #1

Answer:
gases are composed of separated particles, volume occupied is negligible *each individual particle
of a gas has NO VOLUME*



Question:
KMT #2

Answer:
gas molecules are in constant motion, moving in straight paths, colliding in perfectly elastic
collisions (energy is transferred but not lost in the collisions)



Question:

, KMT #3

Answer:
gas molecules do not exert attractive or repulsive forces on one another *no forces attract gas
molecules to each other*



Question:
KMT #4

Answer:
average KE of gas molecules is a sample is proportional to the absolute temperature *KE ~ T*
(increase T= increase E)



Question:
Average Kinetic Energy

Answer:
KE(ave)=1/2mu^2 u=u(rms): root-mean-squared speed of the molecules m: molar mass *speed of
gas particles at a given temp are inversely related to their masses (big move slow)*



Question:
Boyle's Law

Answer:
*V ~ 1/P* & *KMT#2* increase v= decrease p decrease v= increases p



Question:
Charles's Law

Answer:
*V ~T* & *KMT#4* increase T= increase E= increase V