Question

A sample of gas is in a 50.0 mL container at a pressure of 645 torr and a temperature of 25 degreeC. The entire sample is heated to 35 degree C and transferred to a new container whose volume is 65.0 mL. What is the pressure of the gas in the second container? For questions 14 - 16, you have four identical 1.0 L flasks that contain the gases He, Cl_2, CH_4, and NH_3, each at 0 degreeC and 1 atm pressure. Which gas has the highest density? For which gas do the molecules have the highest average velocity? Which gas has the most molecules?

Answer 1

To find the pressure of the gas in the second container after a change in temperature and volume, you can use the ideal gas law.

Step-by-step explanation:

To find the pressure of the gas in the second container, you can use the ideal gas law: PV = nRT, where P is the pressure, V is the volume, n is the number of moles, R is the gas constant, and T is the temperature.

Since the number of moles and the gas constant are constant, we can set up the following equation: P1V1 / T1 = P2V2 / T2.

Using the given values, we have: (645 torr)(50.0 mL) / (25 °C + 273.15) = P2(65.0 mL) / (35 °C + 273.15).

Simplifying the equation and solving for P2, we get P2 ≈ 482 torr.

Answer 2

Pressure in the second container is 0,673 atm

Cl₂ is gas with highest density, He have the highest average velocity, number of molecules is equal for all gases.

Step-by-step explanation:

Using PV = nRT is possible to obtain the moles of gas in a container using:

n = PV/RT (1)

Where:

P is pressure: 645torr* (1atm/760torr)= 0,845 atm

V is volume: 50,0mL = 0,0500L

R is gas constant: 0,082 atmL/molK

And T is temperature: 25°C + 273,15 = 298,15K

Replacing in (1)

n = 1,73x10⁻³ moles

As the entire gas is transferred to a new container (That is every mole was transferred), pressure is:

P = nRT/V

As temperature is 35°C + 273,15 = 308,15K and Volume is 65,0mL = 0,065L

P = 1,73x10⁻³ mol×0,082atmL/molK×308,15K/0,065L = 0,673 atm

Moles contained in the flask are:

n = PV/RT

P = 1atm; V = 1,0L; R = 0,082atmL/molK: T = 273,15K

n = 0,045 moles

As density is ratio between mass and volume and the volume is the same in the four flasks the gas that have the higher mass will be the the highest density.

Molar mass of He is 4g/mol; Cl₂ = 70,9g/mol; CH₄ = 16,05g/mol; NH₃ = 17,03g/mol

As Cl₂ has more mass per mol, will be the gas with the highest density.

Average velocity is:

v = √RT/M

As R is gas constant and temperature is constant, molar mass (M) is the relevant item, that is velocity is inversely proportional to molar mass.

That means the lower molar mass, the highest velocity. That means He have the highest average velocity.

As number of moles is the same for each gas, number of molecules is equal for all gases.

I hope it helps!