Chem 120 Midterm Exam 1 Latest 2023 - 2024

Chem 120 Midterm Exam 1 (Latest 2023 - 2024)

New Full Exam Questions and Answers ( Included ) 100% Correct

• Properties of gases

Answer:

• fill and assume shape of container
• diffuse and mix in all proportions with other gases
• molecules in gas are separated by large distances and interact weakly with each

other

• Variables that describe any gas

Answer:

• nb of moles
• temperature
• pressure
• volume

• Pressure

Answer:

• In Pa
• Force (N)/Area (m^2) - force per unit area
• Force = area x height x density x force of gravity
• So pressure = Height x density x force of gravity

• Atmospheric pressure

Answer:

760 mm Hg 760 torr

• atm

101325 Pa

• Manometer

Answer:

• measure pressure of confined volume of gas
• P(gas) = P(bar) when height of Hg is equal on both sides 1 / 3

• when P(gas) > P(bar), P(gas)= P(bar) + change in P
• when P(gas) < P(bar), P(gas)= P(bar) - change in P

• Ratio of heights (h)

Answer: - inversely related to the ratio of the densities of the liquid (d)

h (H2O)/ h (Hg) = d(Hg)/d(H2O)

• Boyle's law

Answer:

• volume is inversely proportional to pressure
• PV = constant

- V1P1 = V2P2

• Charle's law

Answer:

• low temp = small volume
• high temp = large volume
• V/T = constant

- V1/T1 = V2/T2

• Avogadro's law

Answer:

• equal vol of any ideal gas contain same nb of molecules
• equal nb of molecules occupy equal volumes
• volumes are proportional to coefficients in chemical equation

10. STP

Answer:

• temp = 273.15 K
• pressure = 1 bar = 0.9869 atm
• 1 mol (6.02 x 10^23)
• Volume = 22.7 L
• / 3

• ideal gas equation

Answer: PV = nRT

• General gas equation

Answer: P1V1/n1T1 = P2V2/n2T2

• Molar mass of a gas

Answer:

n = m/M PV = mRT/M M = mRT/PV m= MPV/RT

• Gas density

Answer: d = m/V d= MP/RT

• proportional to molecular weight
• depends on pressure and temperature
• double pressure = double density
• double temperature = half of density

• Gay-Lussac's law

Answer: - gases react in volumes proportional to small whole num bers

• Dalton's law of partial pressures

Answer:

• the total pressure exerted by a gaseous mixture is equal to the sum of partial

pressures of each individual component in a gas mixture

• P(tot) = n(tot) RT/V

• Newton's laws of motion

Answer:

• particles in random straight-lone motion
• separated by large distances so brief collisions
• no long range forces
• gas has internal energy only due to kinetic energy of particles
• total energy is constant
• / 3