Question 1

Which of the following statements about gases is false?

Accepted Answer

Not all gases are colorless and odorless at room temperature. Some examples include chlorine gas (greenish-yellow) and hydrogen sulfide gas (rotten egg smell).

Question 2

A sample of oxygen gas was found to effuse at a rate equal to two times that of an unknown gas. The molecular weight of the unknown gas is g/mol.

Accepted Answer

E

Question 3

Which one of the following is a valid statement of Avogadro's law?

Accepted Answer

Avogadro's law states that at constant temperature and pressure, the volume of a gas is directly proportional to the number of moles of gas present. This can be mathematically represented as V = constant × n, where n is the number of moles and constant is a proportionality constant. Therefore, option C is the valid statement of Avogadro's law.

Question 4

The average kinetic energy of the particles of a gas is directly proportional to _ .

Accepted Answer

According to the kinetic theory of gases, the average kinetic energy of the particles of a gas is proportional to the temperature of the gas, which is directly proportional to the square of the root-mean-square speed of the particles. Therefore, the answer is D, as it is the square of the rms speed.

Question 5

A mixture of two gases was allowed to effuse from a container. One of the gases escaped from the container 1.43 times as fast as the other one. The two gases could have been _.

Accepted Answer

The answer of A mixture of two gases was allowed...

Question 6

The density of krypton gas at 1.21 atm and 50.0 °C is g/L.

Accepted Answer

Using the ideal gas law and the molar mass of krypton, the density is calculated as 3.82 g/L.

Question 7

If one was told that their blood pressure was 130/80, their systolic pressure was .

Accepted Answer

Blood pressure readings consist of two numbers, the systolic pressure (top number) and the diastolic pressure (bottom number). In this case, the systolic pressure is 130 mmHg (millimeters of mercury) and the diastolic pressure is 80 mmHg. Choice B, 80 Pa (Pascal), and choices D and E, 130 Pa and 80 psi (pounds per square inch), respectively, are not valid units of measurement for blood pressure.

Question 8

Of the following, has the odor of rotting eggs.

Accepted Answer

H₂S is hydrogen sulfide, which has a distinct odor often described as smelling like rotten eggs.

Question 9

Which one of the following gases would deviate the least from ideal gas behavior?

Accepted Answer

Ne is a noble gas with a closed shell electronic configuration, which makes it highly symmetrical and non-reactive. Therefore, it experiences negligible intermolecular interactions and deviates the least from ideal gas behavior.

Question 10

Which one of the following gases would have the highest average molecular speed at 25 °C?

Accepted Answer

The average molecular speed of a gas is directly proportional to the square root of its temperature and inversely proportional to the square root of its molar mass. Among the given options, CH4 has the lowest molar mass, hence it will have the highest average molecular speed at 25 °C.

Question 11

At STP, the ratio of the root- mean- square speed of CO₂to that of SO₂is _ .

Accepted Answer

The root-mean-square speed of a gas is given by the formula v(rms) = sqrt(3RT/M), where R is the gas constant, T is the temperature in Kelvin, and M is the molar mass of the gas. At STP (Standard Temperature and Pressure), the temperature is 273K and the pressure is 1 atm. Since both COS and SO2 have the same temperature and pressure, we can cancel these factors out in the ratio. The molar mass of COS is 60 g/mol and the molar mass of SO2 is 64 g/mol. Plugging in these values, we get:
v(rms)COS / v(rms)SO2 = sqrt(3RT/MCOS) / sqrt(3RT/MSO2)
v(rms)COS / v(rms)SO2 = sqrt(MSO2/MCOS)
v(rms)COS / v(rms)SO2 = sqrt(64/60) ≈ 1.207
Therefore, the ratio of the root-mean-square speed of COS to SO2 is 1.207. The answer is B.

Question 12

"Isothermal" means .

Accepted Answer

Isothermal process refers to a process where the temperature remains constant.

Question 13

Of the following, has a slight odor of bitter almonds and is toxic.

Accepted Answer

HCN (hydrogen cyanide) has a slight odor of bitter almonds and is highly toxic. The other options listed do not have this characteristic odor and/or level of toxicity.

Question 14

Of the following, is a valid statement of Charles' law.

Accepted Answer

The answer of Of the following, is a valid statement...

Question 15

A fixed amount of gas at 25.0 °C occupies a volume of 10.0 L when the pressure is 629 torr. Use Charles's law to calculate the volume (L) the gas will occupy when the temperature is increased to 121 °C while maintaining the pressure at 629 torr.

Accepted Answer

Charles's Law states that V1/T1 = V2/T2 for a constant pressure. Convert temperatures to Kelvin: T1 = 25.0 + 273.15 = 298.15 K and T2 = 121 + 273.15 = 394.15 K. Using V1 = 10.0 L, solve for V2: V2 = V1 * (T2/T1) = 10.0 * (394.15/298.15) = 13.2 L.

Question 16

Zinc reacts with aqueous sulfuric acid to form hydrogen gas: In an experiment, 201 mL of wet H₂is collected over water at 27 °C and a barometric pressure of 733 torr. The vapor pressure of water at 27 °C is 26.74 torr. The partial pressure of hydrogen in this experiment is _ atm.

Accepted Answer

To find the partial pressure of hydrogen gas in this experiment, we need to use the total pressure of the gas mixture and subtract the vapor pressure of water at the given temperature.

Total pressure = barometric pressure = 733 torr

Partial pressure of hydrogen = total pressure - vapor pressure of water

Vapor pressure of water at 27°C = 26.74 torr

Partial pressure of hydrogen = 733 - 26.74 = 706.26 torr

We need to convert torr to atm to match the answer choices:

1 atm = 760 torr

Partial pressure of hydrogen = 706.26 torr/760 torr/atm = 0.929 atm

Therefore, the answer is D) 0.929.

Question 17

In ideal gas equation calculations, expressing pressure in Pascals (PA), necessitates the use of the gas constant, R, equal to .

Accepted Answer

The ideal gas equation is PV=nRT where P is pressure, V is volume, n is the number of moles, R is the gas constant, and T is the temperature. The units of R depend on the units used for the other variables. If pressure is expressed in Pascals (Pa), volume in cubic meters (m3), and temperature in Kelvin (K), then R has the value 8.314 J mol-1 K-1.

Question 18

An ideal gas differs from a real gas in that the molecules of an ideal gas .

Accepted Answer

The molecules of an ideal gas have no attraction for one another, whereas real gases have intermolecular forces that cause them to deviate from ideal behavior.

Question 19

A real gas will behave most like an ideal gas under conditions of .

Accepted Answer

When the temperature is high, the gas particles have more kinetic energy, which minimizes the intermolecular forces and allows the gas to behave more ideally. When the pressure is low, the gas particles are more spread out, which also minimizes intermolecular forces, further allowing for ideal gas behavior.

Question 20

A 1.44- g sample of an unknown pure gas occupies a volume of 0.335 L at a pressure of 1.00 atm and a temperature of 100.0 °C. The unknown gas is _.

Accepted Answer

The answer of A 1.44- g sample of an unknown...

Quiz 10: Gases

Which of the following statements about gases is false?

A sample of oxygen gas was found to effuse at a rate equal to two times that of an unknown gas. The molecular weight of the unknown gas is g/mol.

Which one of the following is a valid statement of Avogadro's law?

The average kinetic energy of the particles of a gas is directly proportional to _ .

A mixture of two gases was allowed to effuse from a container. One of the gases escaped from the container 1.43 times as fast as the other one. The two gases could have been _.

The density of krypton gas at 1.21 atm and 50.0 °C is g/L.

If one was told that their blood pressure was 130/80, their systolic pressure was .

Of the following, has the odor of rotting eggs.

Which one of the following gases would deviate the least from ideal gas behavior?

Which one of the following gases would have the highest average molecular speed at 25 °C?

At STP, the ratio of the root- mean- square speed of CO₂to that of SO₂is _ .

"Isothermal" means .

Of the following, has a slight odor of bitter almonds and is toxic.

Of the following, is a valid statement of Charles' law.

A fixed amount of gas at 25.0 °C occupies a volume of 10.0 L when the pressure is 629 torr. Use Charles's law to calculate the volume (L) the gas will occupy when the temperature is increased to 121 °C while maintaining the pressure at 629 torr.

Zinc reacts with aqueous sulfuric acid to form hydrogen gas: In an experiment, 201 mL of wet H₂is collected over water at 27 °C and a barometric pressure of 733 torr. The vapor pressure of water at 27 °C is 26.74 torr. The partial pressure of hydrogen in this experiment is _ atm.

In ideal gas equation calculations, expressing pressure in Pascals (PA) , necessitates the use of the gas constant, R, equal to .

An ideal gas differs from a real gas in that the molecules of an ideal gas .

A real gas will behave most like an ideal gas under conditions of .

A 1.44- g sample of an unknown pure gas occupies a volume of 0.335 L at a pressure of 1.00 atm and a temperature of 100.0 °C. The unknown gas is _.

Quiz 10: Gases

Which of the following statements about gases is false?

A sample of oxygen gas was found to effuse at a rate equal to two times that of an unknown gas. The molecular weight of the unknown gas is g/mol.

Which one of the following is a valid statement of Avogadro's law?

The average kinetic energy of the particles of a gas is directly proportional to _ .

A mixture of two gases was allowed to effuse from a container. One of the gases escaped from the container 1.43 times as fast as the other one. The two gases could have been _.

The density of krypton gas at 1.21 atm and 50.0 °C is g/L.

If one was told that their blood pressure was 130/80, their systolic pressure was .

Of the following, has the odor of rotting eggs.

Which one of the following gases would deviate the least from ideal gas behavior?

Which one of the following gases would have the highest average molecular speed at 25 °C?

At STP, the ratio of the root- mean- square speed of CO2 to that of SO2 is _ .

"Isothermal" means .

Of the following, has a slight odor of bitter almonds and is toxic.

Of the following, is a valid statement of Charles' law.

A fixed amount of gas at 25.0 °C occupies a volume of 10.0 L when the pressure is 629 torr. Use Charles's law to calculate the volume (L) the gas will occupy when the temperature is increased to 121 °C while maintaining the pressure at 629 torr.

Zinc reacts with aqueous sulfuric acid to form hydrogen gas: In an experiment, 201 mL of wet H2 is collected over water at 27 °C and a barometric pressure of 733 torr. The vapor pressure of water at 27 °C is 26.74 torr. The partial pressure of hydrogen in this experiment is _ atm.

In ideal gas equation calculations, expressing pressure in Pascals (PA) , necessitates the use of the gas constant, R, equal to .

An ideal gas differs from a real gas in that the molecules of an ideal gas .

A real gas will behave most like an ideal gas under conditions of .

A 1.44- g sample of an unknown pure gas occupies a volume of 0.335 L at a pressure of 1.00 atm and a temperature of 100.0 °C. The unknown gas is _.

At STP, the ratio of the root- mean- square speed of CO₂to that of SO₂is _ .

Zinc reacts with aqueous sulfuric acid to form hydrogen gas: In an experiment, 201 mL of wet H₂is collected over water at 27 °C and a barometric pressure of 733 torr. The vapor pressure of water at 27 °C is 26.74 torr. The partial pressure of hydrogen in this experiment is _ atm.