Question

495 cm3 of oxygen gas and 877 cm3 of nitrogen gas, both at 25.0 C and 114.7 kpa, are injected into an evacuated 536 cm3 flask. Find the total pressure in the flask, assuming the temperature remains constant.

Answer 1

Answer:

Total pressure of the flask is 2.8999 atm.

Explanation:

Given data:

Volume of oxygen (O2) gas= 495 cm3

                                              = 0.495 L (1 cm³ = 1 mL = 0.001 L)                                            

Volume of nitrogen (N2) gas =  877 cm3

                                               = 0.877 L (1 cm³ = 1 mL = 0.001 L)

volume of falsk = 536 cm3

                         = 0.536 L (1 cm³ = 1 mL = 0.001 L)

Temperature =  25 °C

T = (25°C + 273.15) K

    = 298.15 K

Pressure = 114.7 kPa

               = 114.700 Pa

Pressure (torr) = 114,700 / 101325

                        = 1.132 atm

Formula:

PV=nRT  (ideal gas equation)

P = pressure

V = volume

R (gas constnt)=  0.0821 L.atm/K.mol

T = temperature

n = number of moles for both gases

Solution:

Firstly we will find the number of moles for oxygen and nitrogen gas.

For Oxygen:

n = PV / RT

n = 1.132 atm × 0.495 L / 0.0821 L.atm/K.mol × 298.15 K

  = 0.560 / 24.47

  = 0.0229 moles

For Nitrogen:

n = PV / RT

n = 1.132 atm × 0.877 / 0.0821 L.atm/K.mol × 298.15 K

n = 0.992 / 24.47

  = 0.0406

Total moles = moles for oxygen gas + moles for nitrogen gas

  = 0.0229 moles + 0.0406 moles

n  = 0.0635 moles

Now put the values in formula

PV=nRT

P = nRT / V

P = 0.0635 × 0.0821 L.atm/K.mol × 298.15 K  /  0.536 L

P = 1.554 / 0.536

P = 2.8999 atm

Total pressure in the flask is  2.8999 atm, while assuming the temperature constant.

Answer 2

Answer:

 2.8999 atm

Explanation:

Answer:

Total pressure of the flask is 2.8999 atm.

Explanation:

Given data:

Volume of oxygen (O2) gas= 495 cm3

                                             = 0.495 L (1 cm³ = 1 mL = 0.001 L)                                            

Volume of nitrogen (N2) gas =  877 cm3

                                              = 0.877 L (1 cm³ = 1 mL = 0.001 L)

volume of falsk = 536 cm3

                        = 0.536 L (1 cm³ = 1 mL = 0.001 L)

Temperature =  25 °C

T = (25°C + 273.15) K

   = 298.15 K

Pressure = 114.7 kPa

              = 114.700 Pa

Pressure (torr) = 114,700 / 101325

                       = 1.132 atm

Formula:

PV=nRT  (ideal gas equation)

P = pressure

V = volume

R (gas constnt)=  0.0821 L.atm/K.mol

T = temperature

n = number of moles for both gases

Solution:

Firstly we will find the number of moles for oxygen and nitrogen gas.

For Oxygen:

n = PV / RT

n = 1.132 atm × 0.495 L / 0.0821 L.atm/K.mol × 298.15 K

 = 0.560 / 24.47

 = 0.0229 moles

For Nitrogen:

n = PV / RT

n = 1.132 atm × 0.877 / 0.0821 L.atm/K.mol × 298.15 K

n = 0.992 / 24.47

 = 0.0406

Total moles = moles for oxygen gas + moles for nitrogen gas

 = 0.0229 moles + 0.0406 moles

n  = 0.0635 moles

Now put the values in formula

PV=nRT

P = nRT / V

P = 0.0635 × 0.0821 L.atm/K.mol × 298.15 K  /  0.536 L

P = 1.554 / 0.536

P = 2.8999 atm

Total pressure in the flask is  2.8999 atm, while assuming the temperature constant.