7. Gases

Partial Pressure

Dalton’s Law of Partial Pressures and the Mole Fraction with Examples!

A gas mixture contains 1.25 g N2 and 0.85 g O2 in a 1.55 L container
at 18 °C. Calculate the mole fraction and partial pressure
of each component in the gas mixture.

A mixture of 8.0 g CH4 and 8.0 g Xe is placed in a container and
the total pressure is found to be 0.44 atm. Determine the partial
pressure of CH4.

A piece of dry ice (solid carbon dioxide) with a mass of 20.0 g is
placed in a 25.0-L vessel that already contains air at 50.66 kPa
and 25 °C. After the carbon dioxide has totally sublimed, what
is the partial pressure of the resultant CO2 gas, and the total
pressure in the container at 25 °C?

A flask at room temperature contains exactly equal amounts (in
moles) of nitrogen and xenon.
a. Which of the two gases exerts the greater partial pressure?

 This is the partial pressure of argon.  Use the ideal gas law to find the number of moles of argon. 

 Use Dalton's law to find the pressure of argon and the ideal gas law to calculate the number of moles. 

 This is the total number of moles of all gases present. 

 This is the mole fraction of argon in the container. 

Dalton&#8217;s law states Ptotal = P1 + P2 + &#8230;.

 A 2.50-L container contains a mixture of helium, nitrogen, and argon gas.  The total pressure is 1.800 atm at 295 K.  The partial pressure of helium is 0.650 atm, and the partial pressure of nitrogen is 0.350 atm.  How many moles of argon gas are present in the mixture? 

From the data in Table 18.1, calculate the partial pressures of carbon dioxide and argon when the total atmospheric pressure is 1.05 bar.

Dalton's Law of Partial Pressures Explained

A rigid vessel containing a 3:1 mol ratio of carbon dioxide
and water vapor is held at 200 °C where it has a total pressure
of 202.7 kPa. If the vessel is cooled to 10 °C so that all of the
water vapor condenses, what is the pressure of carbon dioxide?
Neglect the volume of the liquid water that forms on cooling.

Partial Pressure Example 3

A mixture of 14.2 g of H2 and 36.7 g of Ar is placed in a
100.0-L container at 290 K.
(b) What is the partial pressure of Ar in atmospheres?

A gas mixture contains 75.2% nitrogen and 24.8% krypton by
mass. What is the partial pressure of krypton in the mixture if
the total pressure is 745 mmHg?

A 275-mL flask contains pure helium at a pressure of 752 torr. A
second flask with a volume of 475 mL contains pure argon at a
pressure of 722 torr. If we connect the two flasks through a stopcock
and we open the stopcock, what is the partial pressure of
argon?

Pakistan’s K2 is the world’s second-tallest mountain, with an altitude of 28,251 ft. Its base camp, where climbers stop to acclimate, is located about 16,400 ft above sea level. (c) Assuming the mole fraction of oxygen in air is 0.2095, what is the partial pressure of oxygen in mm Hg at the summit of K2?

In a container of unreacting gases, total pressure of the container is the sum of the partial pressures of each gas.

A gas mixture with a total pressure of 745 mmHg contains each
of the following gases at the indicated partial pressures: CO2,
125 mmHg; Ar, 214 mmHg; and O2, 187 mmHg. The mixture
also contains helium gas. What is the partial pressure of the helium
gas? What mass of helium gas is present in a 12.0-L sample of this mixture at 273 K?

A sample of 3.00 g of SO21g2 originally in a 5.00-L vessel at
21 °C is transferred to a 10.0-L vessel at 26 °C. A sample of
2.35 g of N21g2 originally in a 2.50-L vessel at 20 °C is transferred
to this same 10.0-L vessel. (a) What is the partial
pressure of SO21g2 in the larger container?

A heliox deep-sea diving mixture contains 2.0 g of oxygen to
every 98.0 g of helium. What is the partial pressure of oxygen
when this mixture is delivered at a total pressure of 8.5 atm?

A sample of nitrosyl bromide (NOBr) decomposes according
to the equation
2 NOBr1g2 Δ 2 NO1g2 + Br21g2
An equilibrium mixture in a 5.00-L vessel at 100 C contains
3.22 g of NOBr, 3.08 g of NO, and 4.19 g of Br2.
(b) What is the total pressure exerted by
the mixture of gases?

Consider a mixture of two gases, A and B, confined in a closed
vessel. A quantity of a third gas, C, is added to the same vessel
at the same temperature. How does the addition of gas C affect
the following: (a) the partial pressure of gas A?

The apparatus shown here has two gas-filled containers and
one empty container, all attached to a hollow horizontal
tube. Assume that the containers are of
equal volume and ignore the volume of the connecting tube.
Which gas has the greater partial pressure after the valves are
opened?
<img src="https://lightcat-files.s3.amazonaws.com/problem_images/881074c28f595412-1660664740719.jpg" alt="" />

Partial Pressures of Gases and Mole Fractions - Chemistry Tutorial

Dalton's Law and Partial Pressures

A 20.0-L flask contains 0.776 g of He and 3.61 g of CO2 at
300 K.
(a) What is the partial pressure of He in mm Hg?

 Correct, the pressure must be corrected for the partial pressure of water. 

 The pressure must be corrected for the partial pressure of water vapor. 

 Use Dalton's law to find the pressure of hydrogen and the ideal gas equation to find the corresponding number of moles. 

 The pressure needs to be converted to atm. 

 The pressure needs to be converted to atm and the volume to liters. 

When collecting a gas over water, you must consider the vapor pressure of water at that temperature. Ptotal = PH2O + PH2 The partial pressure of water at 25.0&#x2103; is 23.78 mmHg.

 In the reaction of calcium metal and water, 50.0 mL of hydrogen gas is collected over water at 25.0&#x2103; with a total pressure of 752 mmHg.  Calculate the number of moles of hydrogen gas that was produced. 

Air pollution in the Mexico City metropolitan area is among the worst in the world. The concentration of ozone in Mexico City has been measured at 441 ppb (0.441 ppm). Mexico City sits at an altitude of 7400 feet, which means its atmospheric pressure is only 0.67 atm. (a) Calculate the partial pressure of ozone at 441 ppb if the atmospheric pressure is 0.67 atm.

23: Dalton's Law of Partial Pressures and mole fraction

Breathing air that contains 4.0 % by volume CO2 over time
causes rapid breathing, throbbing headache, and nausea,
among other symptoms. What is the concentration of CO2
in such air in terms of (b) molarity, assuming 1 atm pressure and a body temperature of 37 °C?

Assume that an exhaled breath of air consists of
74.8% N2, 15.3% O2, 3.7% CO2, and 6.2% water vapor.
(a) If the total pressure of the gases is 99.8 kPa, calculate
the partial pressure of water vapor.

Natural gas is a mixture of hydrocarbons, primarily methane 1CH42 and ethane 1C2H62. A typical mixture might have Xmethane = 0.915 and Xethane = 0.085. Let’s assume that wehave a 15.50 g sample of natural gas in a volume of 15.00 L at a temperature of 20.00 °C.
(c) What is the partial pressure of each component in the sample in atmospheres?

A mixture of 14.2 g of H2 and 36.7 g of Ar is placed in a
100.0-L container at 290 K.
(a) What is the partial pressure of H2 in atmospheres?

At an underwater depth of 100 m, the pressure is 1.106 MPa.
What should the partial pressure of oxygen be in the diving
gas for the mole fraction of oxygen in the mixture to be 0.21,
the same as in air?

A special gas mixture used in bacterial growth chambers contains 1.00% by weight CO2 and 99.0% O2. What is the partial pressure in atmospheres of each gas at a total pressure of 0.977 atm?

Partial Pressure & Mole Fractions | A-level Chemistry | OCR, AQA, Edexcel

A 1.20-g sample of dry ice is added to a 755 mL flask containing
nitrogen gas at a temperature of 25.0 °C and a pressure of 725
mmHg. The dry ice sublimes (converts from solid to gas), and
the mixture returns to 25.0 °C. What is the total pressure in the
flask?

A gas mixture contains 72.8% chlorine and 27.2% neon by mass. What is the partial pressure of neon in the mixture if the total pressure is recorded as 809 mmHg?

Trimix is a gas mixture consisting of oxygen, helium, and 
nitrogen used for deep scuba dives. The helium is included 
to reduce the effects of nitrogen narcosis and oxygen toxicity 
that occur when too much nitrogen and oxygen dissolve in 
the blood. A tank of Trimix has a total pressure of 200 atm, 
and the partial pressure of He is 34 atm. What is the percent 
by volume of He in the tank? (LO 10.7) 
(a) 17% (b) 38% 
(c) 23% (d) 83%

A sample of 3.51 g argon and an unknown amount of oxygen are mixed in a container at room temperature. The partial pressure of argon was calculated as 71.0 torr and the partial pressure of oxygen as 188 torr. What is the mass of the oxygen within the container?

Partial Pressure Example 1

Mole Fraction and Mole Percent | Given Partial Pressures and Total Pressures| www.whitwellhigh.com

Breathing air that contains 4.0 % by volume CO2 over time
causes rapid breathing, throbbing headache, and nausea,
among other symptoms. What is the concentration of CO2
in such air in terms of (a) mol percentage,

A gas mixture contains each of the following gases at the indicated
partial pressures: N2, 215 torr; O2, 102 torr; and He, 117
torr. What is the total pressure of the mixture? What mass of
each gas is present in a 1.35-L sample of this mixture at 25.0 °C?

The apparatus shown consists of three bulbs connected by stopcocks. What is the pressure inside the system when the stopcocks are opened? Assume that the lines connecting the bulbs have zero volume and that the temperature remains constant. (LO 10.3, 10.7)
(a) 1.10 atm (b) 1.73 atm
(c) 4.14 atm (d) 1.41 atm
<img src="https://lightcat-files.s3.amazonaws.com/problem_images/71125c7f37e00dcb-1669319285651.jpg" alt="" />

A sample of N2O3( g) has a pressure of 0.017 atm. The temperature
(in K) is doubled and the N2O3 undergoes complete
decomposition
to NO2( g) and NO( g). Find the total pressure of
the mixture of gases assuming constant volume and no additional
temperature change.

An 8.40-g sample of argon and an unknown mass of H2
are mixed in a flask at room temperature. The partial pressure
of the argon is 44.0 kPa, and that of the hydrogen is
57.33 kPa. What is the mass of the hydrogen?

Consider the following samples of gases:
<img src="https://lightcat-files.s3.amazonaws.com/problem_images/3cd4bd4b8635dbc5-1664293488257.jpg" alt="" />
If the three samples are all at the same temperature, rank
them with respect to (a) total pressure

A plasma-screen TV contains thousands of tiny cells filled
with a mixture of Xe, Ne, and He gases that emits light of
specific wavelengths when a voltage is applied. A particular
plasma cell, 0.900 mm * 0.300 mm * 10.0 mm, contains
4% Xe in a 1:1 Ne:He mixture at a total pressure of 66.66 kPa.
Calculate the number of Ne atoms in the cell and
state the assumptions you need to make in your calculation.

Partial Pressure Example 2

A sample of 5.00 mL of diethylether 1C2H5OC2H5,
density = 0.7134 g>mL2 is introduced into a 6.00-L vessel
that already contains a mixture of N2 and O2, whose partial
pressures are PN2 = 21.08 kPa and PO2 = 76.1 kPa. The temperature
is held at 35.0 °C, and the diethylether totally evaporates.
(b) Calculate the total pressure in the container.

Natural gas is a mixture of many substances, primarily CH4, C2H6, C3Hg, and C4H10. Assuming that the total pressure of the gases is 1.48 atm and that their mole ratio is 94:4.0:1.5:0.50, calculate the partial pressure in atmospheres of each gas.

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1. Intro to General Chemistry

2. Atoms & Elements

3. Chemical Reactions

4. BONUS: Lab Techniques and Procedures

5. BONUS: Mathematical Operations and Functions

6. Chemical Quantities & Aqueous Reactions

8. Thermochemistry

9. Quantum Mechanics

10. Periodic Properties of the Elements

11. Bonding & Molecular Structure

12. Molecular Shapes & Valence Bond Theory

13. Liquids, Solids & Intermolecular Forces

14. Solutions

15. Chemical Kinetics

16. Chemical Equilibrium

17. Acid and Base Equilibrium

18. Aqueous Equilibrium

19. Chemical Thermodynamics

20. Electrochemistry

21. Nuclear Chemistry

22. Organic Chemistry

23. Chemistry of the Nonmetals

24. Transition Metals and Coordination Compounds

[BOOK CHEM] Clutch Version

Partial Pressure (PGas) is the pressure exerted by an individual gas within a container.

Velocity Distributions

Velocity Distributions represent probability distributions for a gas when examining their molar mass and temperature.

Mole Fraction

Mole Fraction (X) represents the mole component by total moles.&nbsp;

Mole Fraction -

The Ideal Gas Law Derivations

The&nbsp;Ideal Gas Law Derivations are a convenient way to solve gas calculations involving 2 sets of the same variables.&nbsp;

Root Mean Square Speed

Root Mean Square Speed&nbsp;allows for the determination of the velocity of 1 type of gas molecule.

The Ideal Gas Law: Density

Under certain conditions of pressure and temperature, the Ideal Gas Law can determine the density&nbsp;of a gas.&nbsp;

Effusion

Effusion is the escaping of gas molecules or atoms through a pinhole.&nbsp;

Kinetic Energy of Gases

Kinetic Energy is the energy an object possesses due to its motion.

Gas Stoichiometry

Gas Stoichiometry involves chemical reactions that contain gases.

The Ideal Gas Law

The Ideal Gas Law formula relates the behavior of gases under varying conditions of pressure, volume, moles and temperature.

Chemistry Gas Laws: Combined Gas Law

The Combined Gas Law&nbsp;is created from “combining” Boyle’s Law, Charles’ Law, and Gay–Lussac’s Law.

Pressure Units

Pressure is the force that is exerted within a given volume of space.&nbsp;

Kinetic Molecular Theory

A gas is seen as a collection of molecules or individual atoms that are in constant motion. The Kinetic-Molecular Theory tries to use data of real gases to predict how an ideal gas would behave if they existed.&nbsp;&nbsp;

Standard Temperature and Pressure

In order to accurately study the effect that changes in pressure, temperature and moles have on volume, chemists will often run their experiments under Standard Temperature and Pressure.&nbsp;

The Ideal Gas Law Applications

The Ideal Gas Law Applications establish both the direct and inverse relationships between the Ideal Gas Law variables.

Maxwell-Boltzmann Distribution

The Maxwell-Boltzmann Distribution is a probability distribution curve that describes the speed of a gas at a specific temperature.

Chemistry Gas Laws

Chemistry Gas Laws&nbsp;are laws that relate together the pressure, volume and temperature of a gas.

The Ideal Gas Law: Molar Mass

The Ideal Gas Law can be further extended to find the molar mass of a gas.&nbsp;

Van der Waals Equation

The&nbsp;Van der Waals Equation is used when dealing with real, non-ideal gases.&nbsp;