CHM1045 Study Guide - Quiz Guide: Ideal Gas Law, Molar Volume, Gas Laws

Boyles Law

a) A10.0 L sample of a gas at 25oC and 1.5 atm iscompressed at constant temperature to a volume of 1.0 L. What isthe new pressure?

b) A3.5 L sample of a gas at 1.0 atm is expanded at constanttemperature until the pressure is 0.10atm. What is the volume of the gas?

Charless Law

a) A2.5 L sample of gas at 25oC is heated to50oC at constant pressure. What is the finalvolume?

b) Whattemperature would be required to increase the volume from 2.5 L to6.0 L?

Avogadros Law

a) Assumingno change in temperature and pressure, how many moles of methane(CH₄) need to be added to 0.50 moles of methane todouble the volume?

b) 50g of solid carbon dioxide evaporates to carbon dioxide gas atstandard temperature and pressure. What isthe volume of carbon dioxide gas?

Combined Gas Laws

Calculate the temperature when a 0.50 L sample of gas at 1.0 atmand 25oC is compressed to 0.05 L of gas at 5.0atm.

Ideal Gas Law

a) Whatis the volume of gas occupied by 10.0 g CH4 at37oC and 4 atm?

b) Whatis the mass of N2 required to occupy 5.0 L at80oC and 560 mmHg?

Molar Density of Gases

a) Whatis the density of He at STP?

b) Whatis the density of carbon dioxide at 120^oC and 1.5atm?

Application of Gas Laws:

a) How many grams ofNO₂, nitrogen dioxide, are contained in 0.500 L of thegas at STP?

b) Calculate thedensity of NO₂ gas, in grams per liter, at 110C and 12atm.

c) Calculate the molarmass of a gas if 0.125 g of the gas occupies 93.3 mL at STP.

d) On a spring morning(15C) you fill your tires to a pressure of 2.25 atmospheres. As youride along, the tire heats up to 45C from the friction on the road.What is the pressure in your tires now?

e) What volume ofH₂ is formed at STP when 6.0 g of Al is treated withexcess NaOH?

2NaOH+ 2Al + 6H₂O 2NaAl(OH)₄ +3H₂(g)

Application of Gas Law

a) Whatis the effect on the volume of an ideal gas when the temperature isdecreased from 700K to 350K at constant pressure?

b) Whatis the effect on the volume of an ideal gas when both the pressureand temperature are reduced by half?

c) Whatis the effect on the volume of an ideal gas when the pressure ischanged from 722 torr to 0.950 atm, and the temperature is changedfrom 5^oC to 273 K?

Stoichiometric Relationships

a) Howmany grams of phosphorus react with 35.5 L of O₂ at STPto form tetraphosphorus oxide, according to the following reactionequation?

P₄ (s) + 5 O₂ (g)P₄O₁₀ (s)

b) Ammonia decomposes to nitrogen and hydrogen when in thepresence of heated steel wool. What is thefinal volume of the gas when 45 g of ammonia decomposes at150^oC and 1 atm pressure. Writea balanced equation before you start your calculations!

Daltons Law of Partial Pressures

a) A sample of a natural gas contains 8.24 moles of methane(CH₄), 0.421 mole of ethane(C₂H₆), and 0.116 mole of propane(C₃H₈). If the totalpressure of the gases is 1.37 atm, what are the partial pressuresof the gases?

b) Earths atmosphere consist of 78% N₂and 20%O₂, and other gases. What is the partial pressure ofN₂ and O₂intorr, when the atmospheric pressure is 1 atm?

c) Ammonia is completely decomposed to nitrogen and hydrogen, asin question 9b). At the end of theexperiment the pressure of the gas mixture is 866mmHg. Calculate the partial pressures ofN₂ and H₂.

1.) A gas is found to have a density of 3.165 g/L at STP. What is its molar mass? Which of the following gases is it most likely to be?

Molar Mass: _________

a. NH3
b. O2
c. Cl2

d. SF6

2.) Calculate the pressure exerted by 5.05 moles of NCl3 gas in a 20.00-L container at -205°C for a real gas. (for xenon: a= 42.63 atm·L2/mol2 and b= 0.2450 L/mol)

3.) Which of the following is NOT true in the kinetic molecular theory of ideal gases?

The size of the molecules are negligible compared to the volume of the container

The kinetic energy of a sample is proportional to the temperature of the gas.

Collisions are elastic (no friction occurs between the molecules when they collide)

The pressure of a sample is affected by which gases are present.